ATHENS (AFP) - The Athens stock market plunged more than 6 per cent on Tuesday as investors fretted over whether the new far-left government will renege on Greece's international bailout.

The main Athex index opened down 6.39 per cent, reaching a low of 761 points, before recovering slightly to 776 points by 1400 GMT (10pm Singapore time), or 4.59 per cent lower than Monday's close.

The anti-austerity government of Prime Minister Alexis Tsipras, elected Sunday, is set on a collision course with creditors over plans to renegotiate Greece's 240 billion euro (S$363 billion) bailout deal.

The EU has set the end of February as the deadline for Greece to carry out more reforms in return for a seven billion euro tranche of financial aid from the 28-member bloc and the International Monetary Fund.

Tsipras, who has vowed to reverse many of the belt-tightening measures that Greece's creditors insisted on, must decide whether to extend the deadline.