Shadow foreign secretary William Hague has said there will be no going back on plans to withdraw Tory MEPs from the European People's Party (EPP).
William Hague refused to say which groups he had held meetings with
He was speaking after talks in Brussels aimed at forming a new Eurosceptic group in the European Parliament.
Mr Hague also lunched with Tory MEPs, some of whom have said they will risk de-selection rather than quit the EPP.
The former leader of Tory MEPs, Edward McMillan Scott, has dubbed the plan "daft" and "ideologically ridiculous".
Conservative leader David Cameron pledged to sever ties with the EPP during his election campaign, arguing that its federalist view is incompatible with Tory policy.
But critics say that the party would lose influence if it abandoned the biggest political group in the parliament and struck out on its own.
Czechs and Poles
Mr Hague said it was necessary to form a new group in order "to put foward ideas for an open, modern, trading, flexible Europe".
"Those ideas are different from the ideas on reviving the European constitution and many of the federalist solutions favoured by the other parties in the EPP," he said.
The leader of MEPs from the Czech Civic Democratic Party, Jan Zahradil, told the BBC News website his party had reaffirmed its willingness to take the "initial steps" towards setting up a new group with the Tories.
Mr Hague refused to specify which groups he had met, but he told the BBC he had not been talking to "oddballs and fascists" or any French and Italian parties seen as the heirs of fascism.
According to unconfirmed reports, members of Mr Hague's delegation met representatives of two Polish centre-right parties - Law and Justice, and Civic Platform - and also a Dutch MEP, Johannes Blokland.
Mr Blokland's Christian Union includes a Calvinist party, SGP, which refuses to accept women as full members.
Mr Hague was joined at a news conference by the current leader of the Conservative bloc in the European Parliament, Timothy Kirkhope, who acknowledged that many MEPs did not want to quit the EPP group.
Only a handful are keen to abandon the EPP, though most are expected to comply reluctantly.
Up to seven of the 27 Tory MEPs are thought to be ready to defy orders and risk de-selection.
Mr McMillan-Scott said earlier: "Withdrawing from the EPP is not only daft, but it would break a Conservative manifesto pledge to maintain the link until 2009, so Mr Cameron is in effect threatening to deselect those amongst us who would honour the manifesto by refusing to leave the EPP."
He accused Mr Cameron of only pushing for the break to appease eurosceptic supporters on whom he relied for election and said the new Tory leader appeared to be "working towards the centre at home and yet moving to the extreme right abroad as fast as he can".