Evangelos Venizelos faces the task of steering PASOK away from disaster in upcoming parliamentary polls [Reuters]

Greece's finance minister Evangelos Venizelos has declared victory in a vote for the leadership of the socialist party, PASOK, in which he ran unopposed.

Greek state television NET said on Sunday Venizelos, 55, garnered 85 per cent support with 10 per cent of the votes counted.

"We have re-established a relationship of trust for a new start for the party," Venizelos said from the Socialist PASOK party offices in central Athens, the capital.

He now faces the task of steering the party away from disaster in upcoming parliamentary elections, with the socialists in free fall in opinion polls because of harsh austerity measures they have imposed to beat the debt crisis.

NET quoted officials as saying some 200,000 Socialist PASOK members and supporters had turned out to vote, far less than the 750,000 who turned out when former prime minister George Papandreou was elected Socialist leader in 2007.

According to party regulation, leaders are elected in a voting process open to all party members.

Venizelos will take over the PASOK leadership from Papandreou, who was forced to step down as prime minister last November.

PASOK, which has been in government for more than half the time since a junta was toppled in 1974, swept to power in 2009 with almost 44 per cent of the vote under the leadership of Papandreou.

In November, the party entered into a coalition government with the conservative New Democratic party under the leadership of Lucas Papademos, the prime minister.

Venizelos, on whose shoulders the party's hopes for victory in elections expected in April or May rest, will have little time to overcome the dismal popularity ratings following its two years in power.

A recent poll showed PASOK in fifth place, with 11 per cent of the vote ahead of the general election.

Venizelos was appointed to the post of the country's finance minister in June and was a key negotiator for a second, 130-billion-euro ($171.3bn) bailout deal for the country designed to save the country from default.