Three out of five said they believed new elections would be held soon, and just over half said they were not happy with the results of the vote on May 6.
In a separate poll published Sunday by the newspaper Vima, seven out of 10 people said they wanted the parties to form a coalition government.
Syriza would come top if new elections were held, the Vima poll suggested, after coming in second behind New Democracy a week ago. But the results would still lead to a deeply divided parliament, the poll suggested, with no party getting more than 21% of the vote.
In the same poll, six out of 10 voters said Syriza's plans were not realistic. Party leader Tsipras made a radical speech last week against austerity.
The Vima poll appeared to show a fall in support for Syriza since mid-week, when a survey put them first with 28% of the vote.
In Sunday's poll they had the support of 20.5% of respondents. A poll by Metron analysis published on Saturday gave them 20.2%.
Syriza came in second in last week's election with 16.8%.
The party is opposed to the terms of the bailout agreed with the European Union, European Central Bank and International Monetary Fund.
The country's lenders have said that if Greece does not comply with the bailout terms then payments will stop.
Deep uncertainty surrounds the political situation in Greece after large numbers of voters in last Sunday's election backed parties opposed to the country's bailout deal.
Severe austerity measures are required under the terms of the bailout, agreed to by the outgoing coalition government of PASOK and New Democracy.
Headlines in Saturday's papers talk about "Elections on the Titanic" and "Opening the door to an exit from the euro."
Greece has been forced to impose punishing austerity measures to get international loans that have kept it from defaulting on debts so far.
But last week's election results were widely seen as a message to politicians to back away from the economic measures, which include policies to cut spending and raise taxes to reduce public debts.
Seven parties won seats in parliament, but none captured more than 19% of the vote, leading to a week of political turmoil.
The stakes are potentially huge for the rest of the eurozone, the group of 17 European countries that use the euro as single currency.
There is concern that the lack of leadership could jeopardize Greece's bailout agreement. That could lead to a disorderly default by Greece, which would force the nation out of the eurozone.
A default by Greece also could drag down other troubled governments such as Spain and Portugal. The eurozone economy is fragile, and any financial shock could plunge the region into a deep recession, a development that would ripple across the globe.