The Tory leader has said he will not discipline candidates who sign a petition calling for a referendum on withdrawal from the European Union.
" This country really needs a refreshing experience of a referendum on Europe "
The petition was launched on Wednesday by the British Democracy Campaign with a series of newspaper advertisements, funded by millionaire businessman Paul Sykes.
Labour has attacked the petition but the Liberal Democrats have suggested a referendum could allow proper debate on Britain's future within the EU.
So far, seven Labour and four Conservative names are on the petition.
However, a Labour spokesman said party officials had contacted five of the seven Labour names and they had denied signing the petition. The other two are believed to have signed it.
Mr Hague said most Conservative candidates supported the party's policy, which is to "be in Europe but not run by Europe".
"I think a few candidates will have signed it, but not on any significant scale."
He continued: "I think this is a problem of the past in the Conseravtive Party.
"At the last election there were many differing policies in candidates' election addresses, but the overwhelming majority of candidates are clearly very strongly supportive of the party policy on Europe in this election."
Mr Hague said only members of his frontbench team would face sanctions if they signed Mr Sykes' petition.
Conservative Party chairman Michael Ancram told BBC News: "This is a non-event.
"These are four candidates whose views are well known.
"What is important is we have a very clear position as a party and that is supported by the vast majority of candidates."
Cabinet minister Margaret Beckett said: "I think [the campaign] is a bit of a scam.
"But William Hague doesn't seem to mind if half the Tory party sign up to it."
Lib Dem support
However, Liberal Democrat leader Charles Kennedy said he supported the idea of a referendum.
He said while the party would be opposed to the Eurosceptic motives of the petition a referendum could help clear the air.
"This country really needs a refreshing experience of a referendum on Europe.
"We will certainly need one on the euro but the argument has gone off so much in the past decade that any referendum will turn into a full scale debate about Europe and I rather welcome that fact," he said.
"When the facts are put before people I think the people will make the right decision which is to stay in and engage."