(Reuters) - Greece will not accept any return to austerity, leftist Prime Minister Alexis Tsipras said on Monday, adding that he was convinced he would strike a deal with international partners to keep finances afloat.

"The key for an honorable compromise (with the EU/IMF creditors) is to recognize that the previous policy of extreme austerity has failed, not only in Greece, but in the whole of Europe," Tsipras told daily Ethnos in an interview.

Greece's left-wing government won elections in January on a pledge to roll back budget rigor and renegotiate the terms of a 240 billion euro bailout. But it has faced resistance from euro zone partners who are unwilling to offer major compromises.

Although Athens has been granted a four-month extension to the bailout deal, the Feb. 20 accord did not give Greece access to aid pledged to it from the euro zone and the International Monetary Fund, which has led to a cash crunch.

To obtain the remaining aid, Athens must agree on a revised package of reforms. With cash running low, the government has sought to issue more short-term debt, but the European Central Bank has so far refused to give its green light.

Tsipras said the bailout policies of the last five years had led to an unprecedented recession, record unemployment and a humanitarian crisis. Athens could find common ground with its partners based on its proposed reforms, but talks remain tough.

"Whatever obstacles we may encounter in our negotiating effort, we will not return to the policies of austerity," the prime minister said.

Asked whether the government had an alternative plan if its partners continued to refuse it any leeway on its funding needs, Tsipras said he expected the issue would be resolved at this week's EU summit, scheduled for March 19 and 20.

"I don't believe we will need to apply alternative plans because the issue will be solved at a political level by the end of the week in the run up to the EU summit, or, if necessary, at the EU summit (itself)," he told the paper.

Hinting at a possible compromise, Greek Finance Minister Yanis Varoufakis said on Friday that the government was prepared to delay some of its promised anti-austerity measures in an effort to win EU backing.

Asked whether such a delay on implementing his campaign promises was possible, Tsipras said: "This program has a four year time span, and will be implemented fully. The way in which we spread out our work over time depends to a certain extent on the course of the (ongoing) negotiations."