The government has set an "ultimate goal" for Britain to finish fourth in the medals league in the London 2012 Olympic Games, Conservatives say.
Britain came 10th in the medals table at the last Olympics
Tory sport spokesman Hugh Robertson told the Commons he had been sent a document stating this by mistake.
At the last summer Olympics in Athens in 2004, Britain came 10th in the medals table, winning 30 overall.
A government spokeswoman said that no "single definitive" target had been set and that this would depend on funding.
Mr Robertson told the BBC News website that he had asked Sports Minister Richard Caborn in the Commons whether there was a target and that this had been denied.
He had then tried to find out whether there was any target under the Freedom of Information Act.
That request, again to Mr Caborn, had been denied, but a civil servant had accidentally sent him the information - contained in a report by the government body UK Sport.
Mr Robertson said: "We are not happy one little bit. The minister has clearly misled the House."
He added that more funding needed to be made available for sport.
Shadow culture secretary Hugo Swire said Culture Secretary Tessa Jowell was "ultimately responsible for the mixed messages which her minister is sending out".
But a Department for Culture, Media and Sport spokeswoman said: "UK Sport's report spells out not one single option, but a broad menu revealing what impact different levels of investment from government would have on our potential position in the medal table in the 2012 Games.
"The submission starts with a top line option and then works its way down, with reduced amounts of additional funding.
"What we can achieve is determined by what resources we can spend, not the other way round. How can UK Sport set a target if they don't know what the final funding is?
"What Richard Caborn and DCMS have said, in the Commons and outside, is consistent with this.
"Neither the department nor UK Sport have set a single definitive medal target: that will depend on what funds are available to help our potential medallists."
Of Britain's 30 medals in Athens, nine were gold, nine silver and 12 bronze.
The US topped the table with 103 medals, followed by Russia on 92 and China on 63.