The transport minister has refused to say if HS2 will now only go to Birmingham after being asked repeatedly by MPs to clarify rumours that the Manchester leg is being scrapped.
Richard Holden MP was asked to address the "white elephant" in a terse debate in the Commons where he faced criticism for his evasiveness from both Tory and opposition MPs.
It comes as Labour committed to building the high-speed rail lines in full if they win the next general election, following confusion about the party's position.
The multi-billion pound project is intended to "level up" the country by linking London, the Midlands and the North of England with faster trains - but it has been plagued by delays and soaring costs.
Ministers have already scrapped and pushed back parts of the network and there are growing doubts it will ever each Manchester as planned.
Mr Holden said there was "no question of this government abandoning the north", but repeatedly refused to clarify whether the project would run to Manchester.
Louise Haigh, Labour's shadow transport secretary, accused the government of a "great rail betrayal".
She said: "What started out as a modern infrastructure plan left by the last Labour government, linking our largest northern cities, after 13 years of Tory incompetence, waste and broken promises will have turned into a humiliating Conservative failure. A great rail betrayal."
Concerns about the fate of the Manchester leg arose after The Independent published images showing what appeared to be government briefing documents.
These outlined how £2.3bn has already been spent on stage two of the railway from Birmingham to Manchester, but that up to £35bn could be saved by abandoning the phase.
Downing Street has since refused to guarantee that trains will run from the Midlands to the North West as part of the national infrastructure project.
Ms Haigh raised an urgent question in which she asked Mr Holden to "urgently explain if the leaked photograph on Friday reflects his government's position to slash phase 2 altogether?"
He did not answer the question and instead attacked conflicting opinions within Labour about HS2, contrasting senior figure Pat McFadden's cautious answer on the cost of the railway when asked about it by the BBC on Sunday, with the party's commitment to build HS2 and Northern Powerhouse Rail in full in a recent policy document.
However, SNP transport spokesman Gavin Newlands said that "in attacking Labour on cost, he seems to be admitting what we all know - that phase 2 seems to be going. What an utter shambles, financially, operationally and politically".
Conservative MPs also pressed Mr Holden for clarity but he would only say "ministers will continue to keep the House updated as they have done regarding HS2" and that "spades are already in the ground on HS2 and we remain focused on its delivery".
Labour 'will build HS2 in full'
There have already been big cuts and changes to HS2, with the north-eastern leg to Leeds scrapped, construction of the Birmingham to Crewe leg delayed and trains now only running to Old Oak Common in north-west London, rather than the promised Euston terminus if and when the services do begin.
Costs have spiralled largely because of inflation - though critics say delays to construction have made this worse
Some estimates have put the total cost of HS2 at over £100bn while project has been rated "unachievable" by the infrastructure watchdog.
Fresh questions were raised about the fate of the railway on Sunday, when Labour's national campaign co-ordinator Pat McFadden declined to commit to the project being built in full if they win the next general election - despite Labour's "national policy forum" stating this was their position.
However speaking after the Commons debate today, shadow Labour minister Nick Thomas-Symonds told the BBC's PM programme: "We will build HS2 in full and we will build Northern Powerhouse Rail in full.
"That's the clear pledge that we've given. If we do end up in a situation where the Government has spent well over £45 billion on an infrastructure project that isn't even going to go all the way from Birmingham to London, what an indictment of Tory incompetence and waste that is."
Asked to define what building it "in full" meant, he said: "It's both Manchester and indeed the eastern leg... to Leeds."