The country remains on edge with fears that fresh bouts of tribal fighting could break out.
Violence has also forced at least 600,000 people from their homes, mainly in the capital's slums and western region, regarded as the country's breadbasket.
Police said eight houses were burning in a western village in an ethnically motivated attack over the weekend.
A power-sharing deal seemed imminent last week when the government announced both sides had agreed on the establishment of the post of a prime minister and two deputies.
However, the opposition is now threatening to launch new demonstrations if Kibaki fails to call parliament on Wednesday to enact constitutional amendments.
Odinga's Orange Democratic Movement (ODM) insists the opposition leader be given a powerful prime minister post, while the government has offered him a non-executive office.
Koigi Wamwere, a former government minister, said that if Kibaki is agreeing to share power, than the ODM "should have some of those powers".
Speaking to Al Jazeera, he said: "But, once we have set up two centres of power in the same government, once we have set up two governments in one, then a lot of problems will follow.
"Remember, grand coalitions have worked best in countries that are ethnically and racially homogenous. Ours is a multi-ethnic society where ethnic divisions run deep."
Government negotiators maintained on Tuesday that talks were continuing to progress although the opposition was pessimistic.
Musalia Mudavadi, an opposition negotiator, told the AP news agency that the stalemate was "very distressing".
The ODM has given police the required three days' notice for a gathering planned for Thursday.
Past protests have led to violence as police forced back crowds.
The crisis, which has impacted the country's economy, has tapped into simmering resentment over land, poverty and the dominance of the Kikuyu - Kibaki's tribe - in Kenyan politics and business since independence from Britain.