Tory MP Dominic Raab said current extradition arrangements with America, which date from 2003, have been “practically all one way”.
It comes after deputy Prime Minister Nick Clegg unveiled a fresh review of extradition arrangements with the US.
That followed an official review by former appeal court judge Sir Scott Baker found that extradition arrangements with America were balanced and fair.
Mr Raab said that 24 Britons had so far been extradited for trial in the States, while only one American citizen had been forced to stand trial in the UK.
He told a packed Westminster Hall in the House of Commons that in some cases the accused were “plainly and demonstrably innocent”.
British courts had lost sight of the basic principle “that you were innocent until proven guilty”. They should be given discretion to turn down requests, he said.
Mr Raab said: “In practice, as it affects our British citizens, the arrangements [with the US] have been practically all one way.
“The main problem has been any discretion that would allow the UK to deprive extradition in cross-border cases having taken into account the interests of justice.”
Discretion by judges was particularly needed in the case of Gary McKinnon, a 45-year-old computer hacker who suffers from Asperger’s syndrome.
Mr McKinnon has been on bail for a decade, fighting US attempts to extradite him for allegedly hacking into Pentagon and NASA’s network in his search for aliens.
Instead of being treated with sensitivity, Mr McKinnon was equated with “a high-level terror suspect or gangster” by the courts as Home Secretary Theresa May currently decides whether he should be forced to face trial in the US.
David Burrowes MP said the case of Mr McKinnon made it clear why the Baker Review’s conclusions on the extradition treaty with the US were wrong.
He said UK authorities must be allowed to take account of factors including Mr McKinnon’s Asperger’s syndrome.
He told MPs: “He is in his own 24-hour nightmare of anxiety, depression and risk of suicide. He will not be extradited to the US because I am reliably informed he would take his own life – you can take the word of his doctors.”
Mr Burrowes said the treaty needed reopening because “British citizens were sold down the river by these negotiations”.
He added: “It is for Parliament to set out the clear parameters of extradition. It is an issue for politicians, for Parliament and for the Government.”
Keith Vaz MP, chairman of the Commons’ Home Affairs Committee, said he could not see why it had taken so long to decide whether Mr McKinnon should be extradited.
Mr Vaz said: “I cannot see why it has taken 18 months for the Home Secretary to make a decision about this case.
“I have written to her regularly on behalf of the committee and each time she has replied to tell me that medical effort cannot be agreed.”
Sir Menzies Campbell, the former Liberal Democrat leader who has been asked by Mr Clegg to review the extradition arrangements, said the arrangements were unbalanced.
He said: “What would a US Senator or member of Congress be doing were the position to be reversed?
“There is not a Senator or member of Congress who would not be saying what we are saying today – to protect our own citizens.”
Immigration minister Damian Green told MPs said the Government welcomed “the debates that have been happening and the representations that have been made.
“This debate is not at an end. There are going to be more responses to it. They will all feed into the Government’s own consideration of the Baker report.”