Kumaratunga's People's Alliance of parties was left with 111 less than half of the 225 Parliament seats, after the nine lawmakers defected.
Arumugam Thondaman, a member of the Tamil minority with strong union ties among tea plantation workers, resigned from the Cabinet later Wednesday. He did not say whether he and his three party colleagues would oppose the government in the no-confidence vote, still scheduled for Thursday.
Kumaratunga made no public comment on her plans.
When she lost her parliamentary majority in June, following a similar defection, she suspended Parliament for two months to avoid the pending no-confidence vote. She can dissolve Parliament and order new elections, or seek another alliance to give her a majority.
Parliament resumed sitting on Sept. 6 after Kumaratunga formed a temporary alliance with Marxists, which gave her a majority, but prohibited her from seeking any negotiated settlement with separatist Tamil rebels who have been fighting an 18-year war.
The United National Party, the main opposition, brought the no-confidence motions, saying that the government cannot solve the pressing problems of the country, including the war and one of the worst economic slowdowns in years.
The nine defectors include three former Cabinet ministers who had already resigned from their posts after Kumaratunga's agreement with the Marxists.
They include former constitutional affairs minister and deputy finance minister G.L. Peiris, former environmental minister Mahinda Wijesekera and S.B. Dissanayake, former welfare minister and close aide of Kumaratunga.
Dissanayake, one of the first to criticize Kumaratunga's suspension of Parliament, said Wednesday he was opposed to her pact with the Marxists.
Peiris told reporters he left the government because there was Â"rampant mismanagementÂ" and Â"no collective agreement.Â" He said his group of lawmakers will support the no-confidence vote.
After bringing the Marxists into her government, Kumaratunga canceled an Oct. 18 referendum on whether the country needs a new constitution. She had failed last year to push through Parliament a new constitution that would have given autonomy to Tamil areas. It was aimed at wooing moderates away from sympathy with the rebel cause.
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