The timetable for completing the HS2 railway is "complete madness", the head of a Commons committee has warned.
Labour's Margaret Hodge said Parliament would not pass plans by 2015 as there were too many grievances and this would delay completion of the first stage from London to Birmingham beyond 2026.
But Department for Transport (DfT) boss Philip Rutnam said the timescale was "challenging" but achievable.
Last week the government said the estimated cost had risen to £42.6bn.
The previous figure was £33bn.
During heated exchanges with the Commons Public Accounts Committee, Mr Rutnam, the DfT's permanent secretary, defended the figures, saying estimates became more reliable "as you do more work".
'Par for the course'
The revised costs included £22.2bn for phase one of HS2, from London to Birmingham, with £8.2bn of this for contingency funds.
The other £21.4bn, for phase two - from Birmingham to Manchester and from Birmingham to Leeds - included a £5.7bn contingency fund.
Explaining the increase, Mr Rutnam said part of the reason was a demand for increased tunnelling along the route to prevent disruption to people.
But Mrs Hodge, committee chairman and Labour MP for Barking, was highly critical, saying: "When you get an authorisation for a project, you put a number by it... You are sitting there as a minister. You say 'This is what it's going to cost me.'"
Her fellow committee member, Conservative MP Richard Bacon, added: "Everyone thinks it's going to be £70bn, £80bn or £100bn by the time it's finished. That's par for the course, judging by your record."
The committee, which scrutinises value for money in public spending, heard that it was hoped that the parliamentary bill to allow the building of HS2 would become law by 2015, with work starting the following year and the London to Birmingham line being completed before the end of 2026.
Mr Rutnam said: "We are confident that timetable can be achieved. It's a very challenging timetable and we are confident it can be achieved."
But Mrs Hodge, whose constituency was affected by the building of the Channel Tunnel rail ink in the 1990s, said: "This time round you are dealing with every grievance from Hampstead right through every constituency...It's a complete madness."
Several MPs criticised the High Speed Rail (Preparation) Bill in a Commons debate, last week but a bid to quash it was defeated by 325 to 37 votes.
The new high-speed railway line is intended to link London to Birmingham by 2026, with branches to Manchester and Leeds, via Sheffield, planned by 2032.