Prime Minister Christopher Luxon has previewed this week's mini-budget for an economy "under major strain" and echoed previous warnings that the books are not going to look pretty.

Finance Minister Nicola Willis will release the new Government's mini-budget on Wednesday with Treasury also releasing its half-yearly set of economic forecasts.

The minister had previously told Newstalk ZB that the country will have a chance to take a good look at how the economy is faring, to both let them know it's tough "but also that there's hope".

"Going into Christmas, people should know that we're closing a chapter of economic mismanagement we've had over the past six years," Willis said on Sunday.

Talking to Summer Breakfast this morning, Luxon was quick to point to the context in which the mini-budget and the Half Year Economic & Fiscal Update (HYEFU) will be delivered within.

"It's a classic 'National-led Government has to come and clean up the messes', it's really what we've inherited which is an economy in bad shape and deteriorating," he said.

"So the HYEFU will present that up-to-date picture of the economy and the Crown finances and a sort of where-we-are so we have a good starting point."

Luxon said, as Willis had alluded to previously, the announcement will bring a "mini-mini-mini-budget", to lay out the actions taken by the coalition Government over the previous three weeks and the impact it's had on progress so far.

But the Prime Minister noted there had been the need to cut costs from minute one in office.

"You think about the KiwiRail project for ferries across the Cook Strait, that has had a massive blowout in costs which we've had to decline, we've had an Auditor General's report talking about the so-called $15 billion upgrade in NZ Shovel Ready Projects being not being well spent," said Luxon.

"It's gonna take us time to restore the Government books and into top shape again, it'll take us years I suspect, if every year we're being financially disciplined."

The work will need to take place within reports of an economic recession, indicated through three quarters of negative growth. Luxon said he'd been warning the public about where the economy was headed for two years.

"It's just money pumped into the domestic economy rather poorly and it's pumped up what's called domestic inflation," he explained.

"That then leads to interest rates going up, when interest rates go up like they have, it causes pain for mortgage owners but also business owners."

Luxon said this now the economy was beginning to contract and rising unemployment was the next thing to expect, an issue already beginning to occur from what his Government is starting to see.

He believes the nation's goal must be to target the root of inflation, which he put down to Government spending, to do "everything we can to get inflation back under three per cent".

"When we have price stability, we can plan and invest - people know their mortgage rates aren't coming down or going up, gives more discretionary income and they can plan and take on more workers," said Luxon.

"That's a problem economically to fix the economic issues, so that's why we're going through all the Government spending programs to make sure we're not just spraying money around like a firehose."

The mini-Budget is due on Wednesday, alongside Treasury’s Half-Year Economic and Fiscal Update or Hyefu, which sets out the state of the Government’s books and the economic forecasts for the years ahead.

The forecasts will indicate Treasury’s confidence in the new Government’s ability to return the books to surplus. Labour managed to scrape a forecast surplus in 2027. The new Government will be hoping it can manage this too.