"This is not a question one can take a lot of time to tackle," Seibert said. "It is important that the negotiations now come to an end."
Late Tuesday, Greece's private creditors signaled progress on a separate, linked agreement that would cut the country's privately held debt load by 50 percent, or some euro100 billion ($131 billion).
The intention is to ensure that Greece's long-term debts are sustainable. Banks, pension and hedge funds and other private sector holders of Greek debt are expected to swap their current bonds for new ones worth 50 percent less than the original face value, with longer repayment terms and a lower interest rate. They are also expected to get a euro30 billion payment — which is to come from the euro130 billion bailout — as part of the bond swap deal.
Greece has been kept solvent since May 2010 by payments from a euro110 billion ($145 billion) international rescue loan package. When it became clear the money would not be enough, a second bailout was decided last October.
Two years of harsh austerity measures have made Greek voters increasingly hostile.
Some 91 percent of Greeks believe the coalition government is taking the country in the "wrong direction," according to a February tracking poll published Wednesday in Greek daily Kathimerini.
Support for the Socialists, who won a landslide election victory in 2009, has dropped to 8 percent, while the neo-Nazi Golden Dawn group has attracted 3 percent support — enough to achieve representation in parliament, according to Public Issue survey. Conservative New Democracy led with 31 percent, which is not enough to form a government on its own. Sampling data was not available.
Nicholas Paphitis in Athens, Gabriele Steinhauser in Brussels and Juergen Baetz and Geir Moulson in Berlin contributed to this report.