Transport Minister Phil Twyford has labelled claims the Government has canned a number of big roading projects as a "political stunt".
National MP Judith Collins has been "furiously tweeting" about it, Mr Twyford told The AM Show on Friday, but it's "fiction".
"Judith's idea is based on the fact that somehow there were 10 road projects that were going to be four-land, dual carriage expressways, and somehow Labour's come along and pulled the plug on those," he said.
"All they were, were a press release by the National Party during the last election campaign."
National has launched petitions to save its nine planned roading projects, none of which had been approved by the previous Cabinet.
The projects include upgrading the road between Napier and Hastings, the Otaki-Leven expressway and making State Highway 1 between Christchurch and Ashburton four lanes wide.
"Your mob just had nine years in Government," Mr Twyford told Ms Collins, also appearing on The AM Show.
"If you think it was worthwhile spending $15 billion turning those road projects into four-lane motorways, why didn't you do it in the nine years you had in Government?"
Ms Collins told him they were "so busy" with other roading projects.
"If you travel, if you ever get out of Auckland and you go to Tauranga, through to Opotiki... you'll find that's one of our projects. There's also things like coming north from Wellington - that's a place you might know - the Waikato Expressway is an extremely good example. We were busy catching up after you lot had nine years of doing nothing for roads."
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One of National's now-canned upgrades was to the Redoubt-Mill Rd corridor between Manukau, Drury and Papakura - Ms Collins' electorate. Mr Twyford said it was "pork-barrel politics" - accusing Ms Collins of using Government funds to benefit her own electorate.
In turn, Ms Collins has accused the new Government of planning to spend funds collected through petrol taxes and road user charges on rail projects, for example the planned tram to Auckland Airport, which she called a "trolley".
"It's not going to help a lot of people who don't have any train service anywhere near them."
Mr Twyford has previously said funding already allocated for roading projects cannot be redirected, so work on the Redoubt-Mill Rd corridor is continuing.
He said National's petitions are aimed at protecting unfunded campaign promises, not existing projects.
"Since we've been in Government, other than saying the East-West Link has to go back to the drawing board and find a more cost-effective option, we haven't changed the plans for any of those roads," said Mr Twyford.