Toby Perkins, Labour MP for Chesterfield, called on the Government to address Tory MPs who he said were “constantly undermining” the project.
He said: “The recent leaked Network Rail paper, which showed that the alternative to HS2 was 29 years of weekend closures and interminable delay, should be all we need to know about why we need to get on with HS2.”
Transport Secretary Grant Shapps however said those MPs were doing “quite the opposite” or “undermining democracy”.
He said: “It is the case this is the biggest infrastructure decision this country will have ever made [...] and it's quite right that it's properly and carefully considered, not just with that Network Rail evidence, but with everything else. The good news is you won't have to wait too long.”
During transport questions this morning Jason McCartney, Tory MP for Colne Valley, also made the case for HS2 and said the point needed to be made that it was about capacity as well as speed.
He said it also needed to be stressed that “it's not either-or”.
He said: “As well as HS2 we need the TransPennine upgrade, we need Northern Powerhouse Rail, we need a direct Huddersfield to London service, and we also need to upgrade the Huddersfield, Penistone, Sheffield line.
“This would show this Government's real true commitment to levelling up our country and our economy.”
However long-term critic of the project, Shipley Conservative MP Philip Davies, told the Government to scrap the "catastrophic" HS2 scheme.
He said: "If the Government were to scrap HS2, which everybody knows is a catastrophic waste of money, we would have a huge amount available for more rail infrastructure in West Yorkshire and across the North."
He added: "Northern Powerhouse Rail and HS3 is much more important to us than HS2, so what is the Government's intended timetable for completing Northern Powerhouse Rail?"
Responding for the Government, Transport Minister Chris Heaton-Harris said: "HS2 and these various other bits of infrastructure, they're not an either-or, these are additional investments we're making in our infrastructure."
It comes as Chancellor Sajid Javid is set to throw his weight behind the controversial HS2 rail project.
Mr Javid is minded to support the high speed train initiative at a meeting with Prime Minister Boris Johnson and Transport Secretary Grant Shapps on Thursday.
It is understood that having reviewed costs and alternatives the Chancellor will "broadly back" the high-speed line from London to Birmingham, Manchester and Leeds.
Mr Shapps has insisted that no decision on the controversial infrastructure project - the biggest in Europe - will be announced this week.
It has been estimated the scheme, which was allocated £56bn in 2015, could cost up to £106bn.
The Prime Minister told the Commons on yesterday that a decision on the project would be made "very shortly".
He said: "I just want to reassure all of my honourable friends and everybody, whatever persuasion they may be about HS2 across this Chamber, that there will be an announcement and a decision very shortly."
Some £8bn has already been spent on the scheme.
The meeting comes as Mr Javid has put pressure on Cabinet colleagues to identify where cuts of five per cent could be made in their departmental budgets.
In a letter, co-signed by Mr Johnson, the Chancellor urged ministers to identify projects that could be abandoned ahead of his first Budget as Chancellor in March.
The intervention was seen at Westminster as a bid to find resources to fund Tory election promises on infrastructure, health and law and order.
Whitehall's spending watchdog said this month that HS2 is over budget and behind schedule because its complexity and risks were under-estimated.
The National Audit Office (NAO) warned that it is impossible to "estimate with certainty what the final cost could be".
Phase One between London and Birmingham was due to open in 2026, but full services are now forecast to start between 2031 and 2036.
Business chiefs in the north of England have argued that pushing forward with HS2 is key to boosting transport links across the region and providing increased capacity on the overcrowded rail network.
Construction firms warn that scrapping it would cause major damage to the industry.
However, opponents insist HS2 is too expensive and the money would be better spent elsewhere, while several environmental groups say it would cause huge damage to natural habitats and ancient woodland.