Sections of Queensland's M1 motorway will remain in gridlock while the state and federal governments fight over who will pay for upgrades.
The federal government wants the Queensland government to match its $1 billion promise to fix congestion on the M1 between Brisbane and the Gold Coast.
State Transport and Main Roads Minister Mark Bailey says it's a good start, but argues other states are getting a better deal on public infrastructure spending.
Making the funding announcement in Logan on Tuesday, Mr Turnbull repeatedly described the funding as a "game changer" but refused to say whether the federal government would fund the full cost of the upgrades if an agreement couldn't be reached with Queensland.
"The last thing Queenslanders want us to do is get into an argument about who pays what," Mr Turnbull told reporters.
"Queensland has the resources, it has the responsibility. It is Queensland's road after all."
The Pacific Motorway is in fact a federal road, but the Commonwealth argues there is convention for national roads with heavy local traffic to be funded 50-50 with the state, instead of the usual 80-20 funding split.
Federal Minister for Urban Infrastructure Paul Fletcher said Queensland should chip in a similar amount, and wants to see construction underway by 2020.
The announcement comes just days after the federal government pledged $150 million for upgrades to the Bruce Highway north of Brisbane and half of the $352 million needed to build the Rookwood Weir.
Both the federal and Labor state governments claimed credit for getting negotiations this far, after months of wrangling.
Mr Bailey said Mr Turnbull's latest offer was "a bit rich" given the Commonwealth had refused to allocate any money for the state government's $5.2 million cross river rail project, which is estimated to take around 18,500 cars off the M1.
"It's a bit rich for them to say 'No money for Cross River Rail', underfunding infrastructure and then after 30 consecutive negative Newspolls suddenly the money shakes out of the tree," he said.
"They won't work with Queensland. I'm happy to sit down and talk to them about it, they need to be flexible to roll this money out."
The state government has committed $660 million in upgrades to the M1 that are either complete or in the planning phase, according to its figures.
Construction on two other jointly-funded upgrades to the Gateway Motorway merge and on the M1 between Varsity Lakes and Mudgeeraba are due to start soon.
The funding announcement made by Mr Turnbull on Tuesday focuses on two key areas:
* Widening the motorway to six lanes between Varsity Lakes and Tugun and upgrading ramps.
* Widening the motorway to eight lanes between Eight Mile Plains and Daisy Hill while extending the busway to Springwood.