The National Party is launching a series of petitions to drum up support for major highway projects which it says are at risk of not going ahead.
The government derided the move as "misleading" and "nonsensical" and said National never costed or funded many of the promised roads.
National's transport spokesperson Judith Collins said the Labour-led government had wrongly thrown many crucial transport links into doubt.
"Don't keep saying you're not committing. Tell us what you want to do," she said.
"Because right at the moment - after some months in the job - we've still got no idea what they've committed to."
The government had already scrapped plans for Auckland's contentious East-West motorway link and was reviewing other projects around the country.
A Minister of Transport spokesperson said the government had not altered any existing roading project other than the East-West link.
"The Mill Road Corridor upgrade is an Auckland Transport project and planning is continuing.
"It important to note that the other 'highway projects' referred to in National's petition do not exist. They were election campaign promises made by National in August and never costed or funded.
"To suggest the government isn't going ahead with projects that don't exist is misleading."
The affected roads include:
- The upgrade of the Redoubt-Mill Road corridor from Manukau and Flat Bush to Papakura and Drury
- The extension of the Waikato Expressway from Cambridge to the foot of the Kaimai Range, and from Cambridge to Tirau
- The continuous four lane extension of the Northern Motorway from Warkworth to Whangarei.
- An East West Link Road project between the Onehunga-Penrose industrial area and State Highways 1 and 20
- The Tauranga to Katikati Road project as a continuous four lane State Highway with wide lanes and safety measures
- The four laning of the Napier to Hastings Expressway
- The Otaki to north of Levin expressway road project
- The Christchurch Northern Motorway between Belfast and Pegasus
- The construction of the four-lane State Highway 1 link between Christchurch and Ashburton
Ms Collins said the projects had been put at risk by the government's "obsession with Auckland trams".
"Roads from Northland right through to Ashburton are being "reviewed" while the government attempts to divert billions of dollars to pet light rail projects."
A spokesperson for the Minister of Transport said that concern was "unfounded" however, because funding for road upgrades could not be redirected into rail.
"And to suggest non-existing funding be diverted into rail is nonsensical."
National MPs will present petitions to the government later this year.
Tauranga MP Simon Bridges and Hamilton East MP David Bennett will head the petition to extend the link between the Bay of Plenty and Hamilton.
Bay of Plenty MP Todd Muller and Coromandel MP Scott Simpson also announced their campaign championing the Katikati-to-Tauranga four-lane Road of National Significance.
Rangitata MP Andrew Falloon is spearheading the petition to extend the highway between Christchurch and Ashburton to four lanes.