Both sides, however, have offered a glimpse of what is currently on the table.
Broad base
William Ruto, a member of Raila Odinga's opposition Orange Democratic Movement (ODM), confirmed that his party had suggested a power-sharing government.
The proposal includes "forming a broad-based government that lasts for two years", Ruto said.
Odinga has accused Mwai Kibaki, Kenya's president, of stealing the election held in December.
More than 1,000 people have been killed and about 600,000 people displaced since the dispute over the December 27 vote sparked ethnic violence.
Ruto said that during the two years of power sharing, the government should concentrate on reforming the constitution and electoral commission, and establish a plan to rebuild parts of the country which have been destroyed in recent weeks.
He also suggested a truth and justice commission to look into land disputes that have contributed to the ethnic violence.
Proposal received
Mutula Kilonzo, a government negotiator, confirmed that Kibaki's party had received the proposal, and said it would be debated "to see if we can reach an agreement".
Under the current constitution, Kibaki has the power to appoint opposition members into the cabinet, Kilonzo said in an interview with the Associated Press news agency.
For his part, Annan urged Kenyan legislators to enact laws needed to resolve the political turmoil, such as land-reform measures.
"You will need to work together to implement this heavy agenda. Your active involvement across party lines is necessary," he told a special session of parliament on Tuesday.
He said the two parties had already agreed to form an independent commission to look into the electoral commission, which faced heavy criticism for certifying Kibaki's victory in December.
Divided parliament
Mohammad Adow, Al Jazeera's correspondent in Kenya, said: "Parliament is crucial to the whole process. Members of the house will be called to carry out constitutional reforms to enable the implementation of the outcome of the talks."
Parliament, like the country, is divided and acrimony marked the first session of parliament last month.
But Farah Maalim, deputy speaker of parliament, said the legislative body has no option but to co-operate.
He said: "Parliament has no choice. We either have to accept the outcome and proceed on the basis of that, and use this as a transitional parliament ... or we perish."