Plans for the so-called "big bang" expansion of Greater Manchester's Metrolink system will go ahead despite a spending review, an MP says.
The coalition government is reviewing a £170m funding package, agreed in March, to extend Metrolink to Ashton-under-Lyne and Didsbury.
But John Leech, the Lib Dem MP for Withington, told the BBC he was confident the work would go ahead.
Contracts for construction of the lines were signed almost two months ago.
The Treasury has asked all government departments to look at every spending commitment made under the Labour government since January.
Any spending that had Treasury approval - such as the Metrolink fund - has had to be resubmitted, a spokeswoman said.
But Mr Leech - who is also the Liberal Democrats' transport spokesman - said he was "absolutely certain" the project would go ahead.
"The contracts have been signed, it fits perfectly with our plans to have green infrastructure projects to keep the economy going, and I have no concern whatsoever that the funding might be lost.
"As far as the review is concerned, one of the problems is this money was only approved this year and it's this year's projects that are being looked at and reviewed.
"But I've absolutely no doubt whatsoever the Metrolink is coming through to East Didsbury and will go ahead as planned."
Councillor Keith Whitmore, chair of Greater Manchester Integrated Transport Authority (GMITA), said the project was approved in March.
"These projects represent good value for money, bringing considerable social and economic benefits to Greater Manchester.
"Contracts relating to this phase of the Metrolink expansion were signed nearly two months ago, and work is well under way."
The original "big bang" extension - with new lines to Ashton, Oldham, Rochdale and Manchester Airport - was first announced in 2000 but cancelled when costs spiralled.
It was put back on the agenda as part of the £3bn of public transport improvements promised if Greater Manchester accepted a congestion charge.
When that was rejected in a public referendum a slimmed-down extension was suggested, but part of the money needed is from grants the new government is reviewing.