New Zealand's outdated master act for the environment will be scrapped and replaced with three new ones, helping tackle a spiralling housing crisis and climate change threats.

The Government today confirmed it would repeal and replace the Resource Management Act this term - marking one of the biggest regulatory shake-ups in the environment space in New Zealand's history.

Three pieces of legislation will replace the RMA.

In its place would come a core Natural and Built Environments Act (NBA), focused on land use and environmental regulation; the Strategic Planning Act (SPA) pulling together laws around development; and the Climate Change Adaptation Act (CAA) focused on managed retreat and its funding.

While NBA likely won't be passed until later next year, one commentator described the timeline the Government had committed itself to, given the sheer scale of the reforms, as "heroic".

The three new acts were last year recommended by a top-level panel, which found the 30-year-old RMA was failing to protect the environment and lacked national direction, enforcement and input from iwi.

Environment Minister David Parker, who has been open about the need for major change, said urban areas were struggling to keep pace with population growth and the need for affordable housing.

At the same time, water quality was deteriorating, biodiversity was diminishing and there was an "urgent need" to slash carbon emissions and adapt to climate change, he said.

Other key changes confirmed today include one single combined plan per region - something last year's Randerson report had also called for.

The NBA would come with a mandatory set of national policies and standards to support natural environmental limits and targets specified in the new law, and these would also be incorporated into the regional plans.

This effectively meant the more than 100 RMA planning documents used by New Zealand's 78 councils would be squashed down to about 14.

The SPA would meanwhile fold together functions under the RMA, the Local Government Act, the Land Transport Management Act and the Climate Change Response Act.

"New spatial strategies will enable regions to plan for the wellbeing of future generations, ensuring development and infrastructure occurs in the right places at the right times," Parker said.

He acknowledged that secure, healthy and affordable housing was "no longer a reality" for many Kiwis - and urban areas home to 86 per cent of the population were seeing 99 per cent of population growth.

"Instead of allowing cities to respond to population growth sustainably, poor quality and restrictive planning has contributed to a lack of certainty and unaffordable housing," he said.

"Housing problems are a complex mix of demand, costs, financing, capacity and supply and there is no silver bullet."

Those were worries that also came through strongly in last year's Randerson review.

"Poorly managed urban growth has also led to increasing homelessness, worsening traffic congestion, increased environmental pollution, lack of transport choice and flattening productivity growth," it stated.

Some councils - particularly in high-growth areas – were now struggling to provide enough development capacity for housing in regulatory plans, along with enough infrastructure to support urban growth.

At the same time, rapid changes in rural land use had heaped even more pressure on our straining natural ecosystems.

Parker said the planned reforms would help here by improving how central and local government planned for housing and urban development.

This included better coordination of future infrastructure with land use, development and urban growth, he said.

The changes would build on the National Policy Statement for Urban Development released last year, that directed councils to make room for growth both "up" and "out".
Parker said the NBA would be progressed first.

"Given its significance and complexity, a special select committee inquiry will consider an exposure draft of the NBA Bill from mid-year," he said.

"This will include the most important elements of the legislation, including the replacement of Part 2 of the RMA."

He expected the complete NBA and the SPA to be formally introduced into Parliament by the end of this year, with the NBA passed by the end of next year.

The CAA, meanwhile, would be progressed by Climate Change Minister James Shaw.

Nationally, about 450,000 homes that currently sit within a kilometre of the coast are likely to be hit by a combination of sea level rise and more frequent and intense storms under climate change.

Experts have warned that insurers could start pulling cover within the next 15 years - and councils have urged better direction and resourcing from Wellington to meet the challenge.

The Government was already working on the reforms with a group of council chief executives, along with a collective of several Māori entities.

As the RMA met with 60 pieces of Treaty of Waitangi settlement legislation, consultation with iwi would be crucial.

Today's announcement was welcomed by Local Government New Zealand, whose vice-president Hamish McDouall pointed to the strain councils now faced.

"The fact is that the growth strategy of successive governments has hinged on large population increases, to the tune of half a million arrivals in half a decade," he said.

"While this has brought much needed skills and expertise to our country, it's also put pressure on the planning system, which means our housing and infrastructure, particularly in urban areas, hasn't kept up with population growth."

The Act Party, which has long campaigned on RMA reform, was more sceptical about the plans, and argued they didn't strike a balance between upholding rights of property owners and making it easier to develop land.

"Labour is proposing to set up new agencies with new regulatory powers that essentially cut and paste the worst elements of the RMA into three new pieces of legislation," the party's environment and local government spokesperson Simon Court said.

"This will tie land up in planning purgatory for another decade and have the effect of increasing red tape and the cost of housing and doing business."

Environment groups meanwhile met the moves with cautious optimism.

Environmental Defence Society president Gary Taylor said the Government's set timeline for enacting all three new acts was "heroic" but also doable.

His group supported the Government's approach of having a two-stage stage select committee hearing process.

"The EDS will be watching carefully to ensure that environmental bottom lines are effectively expressed in the new law and that clear national direction on key issues like freshwater quality is properly enabled."

Greenpeace Aotearoa executive director Dr Russel Norman said it was hopeful that the new legislation would include biophysical limits.

"The test of the new legislation will be exactly what those limits are and whether these public interest environmental protections trump private profit driven applications."

Particularly, Norman said whatever replaced the RMA had to effectively regulate dairying pollution, such as nitrates from over-stocked farms, milk processing and synthetic nitrogen fertiliser entering waterways.

The Randerson report had noted that, between 2002 and 2016, for instance, there was a 42 per cent increase in the proportion of farmland used for dairy, and a decrease in the area used for sheep and beef.

There was also continued intensification of land use and a shift to higher stocking rates.

"In farming areas, water pollution affects almost all rivers and many aquifers – which in turn affects the mauri of the water, human health and our ability to swim and enjoy our water for recreation," it said.

Timeline

April 21: Further policy decisions for the exposure draft and consultation material are developed.

May 2021: Cabinet approves final exposure draft of the NBA and consultation material and presents it to House.

May-September 2021: Exposure draft referred to special select committee inquiry.

June-December 2021: Cabinet considers remaining policy decisions.

December 2021: NBA introduced into the House and then follows standard legislative process.