Lord Deighton said the Coalition should "milk" the high speed rail project and not "moan" about, suggesting that private investors would be found.
Doubts about the rising cost of the UK Government's £50 billion flagship project grabbed headlines when Alistair Darling, the former Labour Chancellor, came out against it, saying he feared it would drain money away from other transport infrastructure schemes.
Last month at the Labour Party conference, Ed Balls, the Shadow Chancellor, caused a stir when the Opposition's support became heavily conditional on the costs not rising any further.
Lord Deighton stressed "consensus is critical" and did not think Labour would pull the plug if it got into power. "The essence of his warning was 'if this is out of control, we'll have to think again'."
The Commercial Secretary to the Treasury, who helped deliver last year's Games on time and on budget, made clear HS2 would achieve the same aim.
Lord Deighton noted how the taxpayers were stumping up a large amount of money, so the need was to do it in a "world-beating way". He said it was still "very early days" in terms of putting in place a public budget for HS2 but made clear "over time we will see if there are opportunities to introduce private finance".
The initial stage will be London to Birmingham by 2026, taking 49 minutes and saving 35, and then onto Manchester by 2032, taking 68 minutes, saving an hour. The project is also set to take an hour off the journey from Scotland to London.
An interim Coalition report on HS2 will be out later this month with a full one published in February.