Newly appointed Infrastructure Minister Chris Bishop has slammed the latest report on the previous Government's spending, calling it "one of the most damning” he has read.

Auditor-General John Ryan’s report on the $15 billion NZ Upgrade Programme and Shovel-Ready Projects found Labour ministers had made decisions against advice and that it was unclear where the money had gone.

"It's a shocker," Bishop said.

On the Mike Hosking Breakfast show this morning, Bishop said in one case, ministers had announced a project and Auckland Transport, which was receiving the money and would be delivering the project, found out about the Government's plans through the national news.

"There wasn't even any engagement with them, it's just a disgrace," said Bishop.

Mike Hosking asked if it was fair to say the previous Government had the worst track record when it came to ignoring advice, Bishop said it was "very fair" to conclude that - particularly when it came down to transparency and accountability around infrastructure projects.

Bishop labelled the "so-called shovel-ready projects" a disgrace and noted the auditor general had backed up the claims he'd made during his two years in opposition.

"Ministers created for themselves a $3 billion slush fund to announce in the middle of the election [it was announced in mid-2020 ahead of that year's election] and it let ministers go around the country during the election campaign and say they were funding projects in regions all around the country," he said.

"Now in some cases, the projects they announced were not recommended by the officials. So the criteria drawn up by officials were ignored - so they just added them at the last minute - the transparency of how that happened is completely unclear."

“In some cases, they weren't even shovel-ready. There were some so-called shovel-ready projects announced in 2020 that are still yet to start - and here we are in late 2023."

Bishop said the previous government’s actions showed contempt for the public's money on a grand scale.

"The fiscal vandalism of the last Government is now coming home to roost and sadly, this Government is gonna have to clean up the mess left by the last Labour Government," he said.

"[Finance Minister] Nicola Willis will start that with the mini-budget very soon."

Hosking asked if the auditor general’s report meant the new government would need fund things differently - Bishop agreed, but noted there was still a need to fund things.

"We've got a big infrastructure deficit in New Zealand and we need to tackle it," he said.

"And we've talked quite openly about doing things differently, so we need to use new tools."

The tools he suggested included an increase in toll roads, public-private partnerships and "innovative financing arrangements", such as value capture tools and build-and-lease arrangements.

"There's no silver bullet to our infrastructure deficit but I tell you what we won't be doing - we won't be taking advice from the last Labour Government and will engage with the recommendations from the auditor-general inquiry.”