Sri Lanka's main opposition has accused the government of taking a cavalier and casual attitude towards the peace process with Tamil Tiger rebels.
The president wants to focus on a final solution, not power-sharing
United National Party spokesman GL Peiris said the government had again changed its stand on resuming talks.
The government now insists negotiations should focus on a final settlement rather than temporary power-sharing.
Separately, President Kumaratunga has quit as leader of the governing alliance "due to pressure of work".
The decision is not expected to affect the day-to-day running of the government.
Issue of trust
In a meeting of governing party lawmakers this week, Mrs Kumaratunga is understood to have ruled out talks with the Tigers on the basis of their proposal of an interim administration.
The government wants the talks to focus on a final settlement, something which is not acceptable to the Tamil Tigers at this stage.
According to Mr Peiris, the new Sri Lanka Freedom Party-led coalition government's position was inconsistent.
Only a few weeks ago, the president had assured Norwegian mediators the government was keen to resume peace talks, Mr Peiris said.
The BBC's Sanjeev Srivastava in Colombo says there is also the issue of trust, or the lack of it, between the Tamil Tigers and the new rulers, which is adversely affecting the peace process.
Despite repeated denials by the government, the Tigers believe a breakaway rebel, Colonel Karuna, is being supported by the army and a section of the new government.
With no progress on peace, the ceasefire signed in February 2002 looks increasingly fragile, our correspondent says.
Analysts say Mrs Kumaratunga's decision to resign as leader of the Freedom Alliance coalition is an attempt to sideline her Marxist ally, the JVP.
The Marxists have consistently opposed any concession to the Tamil Tigers.
Already the level of violence has escalated, with several killings in the east of the island and a suicide bombing in the capital in the past few weeks.