A spokesman for the Greek government has said it does not need to activate an EU-IMF debt rescue mechanism 'at this time'.
George Petalotis said: 'We do not need to activate or modify any mechanism. There is no need for any initiative at this time.'
Mr Petalotis was speaking amid growing speculation that Greece would have to seek help to resolve its debt and deficit problems.
European Central Bank head Jean-Claude Trichet meanwhile insisted that the deal remained a 'workable framework'.
'Taking all the information I have, a default is not an issue for Greece,' Mr Trichet insisted.
The deal was worked out last month by EU states to also involve the International Monetary Fund.
Amid rising doubts that the EU would stick by the deal, the yield on Greece's key ten-year bonds soared to a record high and the Athens stock market registered its heaviest losses in weeks.
The yield or return on Greek ten-year bonds topped 7.5% for the first time since Greece adopted the euro in 2001.
However, by mid-afternoon it had come back to around 7.35%, which is still more than double the rate on the German ten-year bond at 3.09%.
Finance Minister George Papaconstantinou said Greece 'is borrowing and will keep on borrowing' despite the record high costs imposed by financial markets.
'Our goal is not the daily fluctuation of interest rates but the restoration of the country's credibility,' he said.
The government says it has covered its payment needs for all of April and now has May to consider, after which it believes interest rates on its debt will fall as its new bond issues decrease in size.
The Athens stock exchange slumped more than 5% and banks were heavy losers a day after the Bank of Greece governor said major lenders wanted to draw funds from a dormant state support scheme.
Greece is mired in a deepening recession and is trying to reduce a mountain of debt of nearly €300bn.
It faces a huge task to cut its budget deficit by 4% this year from an official level close to 13% of output.
