The popularity of Greece's two main political parties, which have backed the country's coalition government, continues to deteriorate, a public opinion poll showed Thursday.

A growing number of voters intend to support smaller left-wing, anti-bailout and right-wing parties in a protest vote against the incumbents due to anger over ongoing austerity measures, according to the poll.

A nationwide poll by the private Skai television station and the Kathimerini newspaper sees the two major parties--the Socialists, or Pasok, party and the conservative New Democracy party--would garner only 36% of the vote if elections were held today. Specifically, New Democracy would command 25% of the vote and Pasok just 11%, while seven other parties--up from just three now--would also be represented in parliament.

Based on poll numbers, it appears that the election to replace the current caretaker government could yield a fractured result that would require the creation of a multiparty government to follow through on promised changes to continue to qualify for a new EUR130 billion ($170.12 billion) bailout package from international lenders.

Leftist parties, which openly oppose the austerity measures, continue to hold great popularity among voters. The poll said the Stalinist KKE is backed by 11.5% of voters, the newly formed Democratic Left by 15.5% and the Coalition of the Left by 12%. The party called the Ecologist Greens received 4% support.

The same poll indicates that small, right-wing nationalist Laos party would receive 4% of the vote--down from a recent peak --while the newly formed Independent Greeks would command 6.5%. It also shows that extreme-right neo-Nazi Golden Dawn party is backed by 3% of voters-which is the minimum threshold needed to enter parliament.

The latest poll confirms other recent surveys showing a progressive fragmentation in Greece's political landscape with more of the smaller parties entering parliament.

Another poll published earlier Thursday showed Greeks' growing disaffection with radical government austerity. The poll, published in the weekly To Pontiki newspaper, indicates that New Democracy would command 17% of the vote and Pasok just 10%.

Adjusting for undecided voters, the poll shows that New Democracy would command 116 seats in parliament--taking into account a 50-seat bonus awarded to the leading party under Greece's electoral system--not enough to form a governing majority in the 300-member parliament. The Socialists, who formed an interim coalition government with New Democracy in November, would control just 39 seats.

Some 73% say that the state of the economy will probably affect their vote, and almost nine in 10 Greeks--88%--said their financial position had deteriorated in the past two years.

Although no official date has been set, Greece is widely expected to go to elections in the next several weeks with the most likely dates being April 29 or May 6, after the current interim government of Prime Minister Lucas Papademos finalizes the EUR130 billion bailout for the country and concludes an associated debt restructuring.

The survey was carried out on March 8-13, after Greece concluded a successful bond swap.

-By Nektaria Stamouli, Dow Jones Newswires; +30 210 373 1775; nektaria.stamouli@dowjones.com