KiwiRail's releasing its full Commercial Review to give New Zealanders a closer look at the options tabled to improve its competitiveness.

In 2014, the review gave bold options to the Government, including trimming the network or closing the rail freight business entirely.

The Government decided not to opt for those, and allocated two years investment to the national rail network in 2015's budget.

KiwiRail chief executive Peter Reidy said as a publicly-owned company and complex business, people will be interested to see what the report showed.

"We thought it was important that we outlined all the thinking and the analysis to the market, but as I said time's moved on, the Government's made its decision and they've fully decided to invest in us and they realised they are a long-term holder of the KiwiRail network."

Green MP Julie Anne Genter said the Government should let KiwiRail compete for funding from the roading budget and scrap the current two tiered funding system.

"If rail was able to compete for some of that funding, I have no doubt that we would find there is an incredibly cost-effective infrastructure investment that we could be making in the rail network from that budget that would benefit the road network and the economy."

Labour MP David Parker said the Government needs to provide long term secure funding so the company can plan for the future and not have to consider scrapping essential freight and ferry systems.

"Because if you don't properly fund rail what happens is you have more trucks on the roads, and you have to spend more money on roads, so you save money by supporting New Zealand rail."