Greece’s Prime Minister Alexis Tsipras has told rebels in his Syriza party he will have to call early elections if they continue to oppose a bailout deal.
The agreement is likely to see up to €86bn (£60bn; $94bn) released in exchange for economic reforms.
But some Syriza members see the deal as breaking their pre-election promises to end austerity.
Mr Tsipras said he would be “forced” to go to the polls unless he has a majority in parliament.
He stressed he wanted to see the bailout programme completed while in office.
“I would be the last person to want elections, if I had the secured parliamentary majority to make it through to the end of the four-year term,” Mr Tsipras told the Sto Kokkino radio station.
He had to rely on opposition support earlier this month to push an initial package of measures through parliament demanded by Greece’s creditors to open negotiations on the deal. More than 30 Syriza members rebelled.
More controversial reforms, including phasing out early retirement and tax rises for farmers, have been pushed back until August.
With talks on the bailout now under way, Mr Tsipras said he would hold a special congress on Syriza’s future, likely to be in early September once the negotiations have wrapped up.
He said he faced “surreal” behaviour from some in his party, who voted against the economic proposals but still said they supported the government.
Mr Tsipras himself has said he does not believe in the deal, but said it was the only way to keep Greece within the euro.