Prime Minister Alexis Tsipras failed to secure the backing of Greek opposition parties on Saturday for tough pension reforms the country has promised to submit by December under its international bailout.
The leftist government has already raised the retirement age and health care contributions and scrapped most early retirement benefits to get part of the financial aid promised by its European lenders.
But Athens needs to introduce deeper reforms by the end of the year to make its ailing pension system viable, including merging several pension funds into one and cutting back supplementary pensions.
Tsipras called a meeting with center-left, center-right and centrist opposition leaders to seek a broader consensus when the reforms come before parliament after his government's majority shrank to just three seats this month.
But they rejected his call to create a joint committee to prepare proposals on pension reforms, a senior Greek government official told reporters after a six-hour meeting.
"At this crucial turning point, the country needs more than ever national unity, popular unity and political stability," Tsipras said in a televised speech after the meeting.
"The strategic plan to pull the country out of the crisis and regain our sovereignty from the lenders will succeed."
He said the government would table a proposal on the pension reform.
A joint statement said only that there should be extensive debate when the bill comes to parliament to ensure a viable pension system and avoid further cuts in benefits.
"The opposition didn't live up to expectations. They rejected the plan presented by the prime minister on the pension reforms," the official said.
"The country has committed to taking (additional) pension reform measures worth 1 percent of GDP. The government has already found measures equal to 0.6 percent of GDP and called on the political leaders to agree on the remaining 0.4 percent," the official said.
The main center-right opposition party, New Democracy, is in disarray after having to postpone a leadership ballot after it lost a general election to Tsipras' Syriza party in September. The other parties who attended the meeting were the moderate Socialist PASOK, the centrist To Potami, the Union of Centrists, and the rightist government coalition Independent Greeks.
The hard left KKE communists did not attend the talks at the president's residence and the extreme-right Golden Dawn was not invited. Both have seats in parliament.
Greece and its international lenders agreed this week on a new set of reforms the country must approve in December to qualify for an additional 1 billion euros in aid.
Pension reforms are not part of this list but remain a key issue to complete the first review of progress under its bailout program and open the way for negotiations on debt relief.
Greeks are strongly resisting the reforms, weary after years of crisis which has hurt their incomes, jobs and living standards. Thousands of pensioners demonstrated in central Athens on Thursday against cuts, while the biggest public and private sector unions called a 24-hour strike against the reform on December 3.