ATHENS (AFP) - Struggling Greece will keep on repaying its European Union-International Monetary Fund (IMF) creditors for as long as it can, with some 300 million euros (S$441.7 million) due next week and no deal in talks over the country's remaining bailout funds, a spokesman said on Monday.

"To the extent that we are able to pay, we will keep on repaying these obligations," government spokesman Gabriel Sakellaridis told reporters. "It is the government's responsibility to be able to repay all these obligations.... It is also the responsibility of the creditors to be faithful to (their) loan obligations."

Mr Sakellaridis' remarks came a day after a Cabinet minister said Greece had "no money" to make a series of repayments to the International Monetary Fund from June 5. "The instalments for the IMF in June are (overall) 1.6 billion euros. This money will not be given. There isn't any to be given. This is a known fact," Interior Minister Nikos Voutsis said on Sunday.

Greece's radical-left government has been locked in negotiations with its creditors - the IMF, the European Union and the European Central Bank - for the past four months in a bid to unlock some 7.2 billion euros in bailout cash.

The Syriza-led government, which was elected in January on an anti-austerity platform, has so far refused to agree to key economic reforms that the creditors want in exchange for the rescue funds.

But with a punishing debt repayment schedule in the next three months, the country now desperately needs those funds.

Last week, the parliamentary spokesman for Syriza had also said that the government would be unable to honour repayment to the IMF as its priority is to pay salaries, pensions and running costs.

"No country can repay its debts with only the money from its budget," Mr Nikos Filis told Ant1 television.

Mr Sakellaridis also said talks in Brussels over the Greek reforms would resume on Tuesday.

He added that the two sides were still apart on tax issues, social insurance, labour rights and the size of Greece's budget surplus.

He repeated that the government's goal was to secure a "mutually beneficial" agreement by early June at the latest.

"Austerity is the only deal-breaker," Finance Minister Yanis Varoufakis wrote in a Project Syndicate blog entry.

"Greece's creditors insist on even greater austerity for this year and beyond... Our government cannot - and will not - accept a cure that has proven itself over five long years to be worse that the disease," he wrote.

Mr Sakellaridis denied a report by Greece's Mega TV that Prime Minister Alexis Tsipras had asked US Treasury Secretary Jack Lew to help persuade the IMF to agree to group all four June repayment instalments to the end of the month.

"I read these reports, there is no such case. We have not examined it and no such case has been put to the Greek government," he said.

The spokesman also dismissed speculation of possible capital controls - meaning limits on cash withdrawals - being imposed over next weekend if no deal emerges.

"Such scenarios are entirely baseless and malicious... There is absolutely no possibility of capital controls," he said.