Chancellor John Healey has said building a third runway at Heathrow Airport has "always been a case for growth", after Prime Minister Andy Burnham refused to say whether he backed the expansion.
Speaking from the International Monetary Fund (IMF) meetings in Bangkok, Healey said that airport expansion, including at Heathrow, had been "a big part of jobs and growth" in recent decades.
His predecessor Rachel Reeves had put Heathrow expansion at the centrepiece of an argument that Britain is open for business.
But Burnham has been more sceptical about the case, telling the BBC it was "a matter for London and Londoners".
It follows a warning earlier this week from Heathrow's chief executive, who said that not building a third runway at the UK's busiest airport would be a "huge missed opportunity".
Building a third runway at Heathrow has been debated for decades, with the project facing steep opposition from local residents, politicians and climate campaigners.
Last year, Reeves announced the government-backed expansion, saying "a third runway is badly needed", and the government could not "duck the decision any longer".
Asked about the project last month, Burnham suggested it is an argument for London to decide.
"I think we ought to hear the voice of people there first. It's not right for me to just jump straight in on the back of the consultation," he added.
The Department for Transport has said it is "considering the appropriate next steps" following the public consultation on its National Policy Statement, which provides the basis for deciding whether to grant a new runway at Heathrow.
"The formal position now is that the consultation is closed, led by the Transport Department. We're reviewing those, and then further decisions and announcements will follow," Healey told reporters.
The airport's consortium of owners has said they need explicit backing from Burnham before the end of the year in order to proceed with the project.
Speaking to BBC Radio 4's Today programme earlier this week, Thomas Woldbye, the airport's chief executive, said it would be "good to know" the government's position on the project.
He said he hoped the prime minister would "come along" with the project, adding that a third runway was "not just for Londoners".
"Benefits will be felt all over the country because our supply chain reaches all the way from the north all the way to the south of the UK," Woldbye said.
Heathrow serves more than 80 million travellers a year with its four passenger terminals and two runways. The number of flights, currently capped at 480,000 a year, could go up to 720,000 - or nearly 2,000 a day on average, if a third runway is built.
The project, which has an estimated price tag of £33bn, would see hundreds of homes demolished, rivers diverted and the M25 motorway rerouted through a tunnel between junctions 14 and 15.
The new runway was scheduled to open by 2035, subject to plans being submitted and approved, but Heathrow has since suggested it would be delayed by four years to 2039 due to planning and regulatory issues.