The countdown to the crucial floor test to prove if Chief Minister H.D.Kumaraswamy-led coalition government in Karnataka has a majority began on Tuesday, with the Assembly resuming debate on the confidence motion.

"The floor rest will take place after the debate and the Chief Minister's reply to the motion he moved on July 18. All the members have been notified to be present in the Assembly for the trust vote," a legislature official told IANS here.

The opposition BJP is upbeat about the imminent fall of the 14-month old Janata Dal-Secular (JD-S)-Congress coalition government with 15 of its rebel legislators vowing to abstain from the session ignoring a whip issued by their parties to remain present or face disqualification.

The Speaker has also summoned the 12 rebel Congress MLAs at 11 a.m. today, but they have sought four weeks' time to meet him pleading they are not in a position to return to Bengaluru for personal reasons.

"The Supreme Court on July 17 ruled that the 15 rebel legislators, including 12 of the Congress and 3 of the JD-S cannot be compelled to attend the Assembly for the trust vote, as they have already resigned. Therefore the whip will not be applicable to them," a senior advocate told IANS here.

Besides the 15 rebels, two Congress legislators - Srimanth Patil and B. Nagendra - are unlikely to be present in the House for the floor test, as they are in hospital.

"Patil has informed the Speaker that he is hospitalised in Mumbai and Nagendra conveyed that he is admitted in a Bengaluru hospital," the official said.

With two Independents - R. Shankar and H. Nagesh - having switched loyalty from the ruling alliance to the BJP after resigning as ministers on July 8, the BJP has 107 members, including 105 of its own.

Though Bahujan Samaj Party's (BSP) member N. Mahesh said he would vote in favour of the motion, the ruling combine still falls short of 17 legislators in the absence of 15 rebels and two Congress members, who are in hospitals, for the floor test.

With the strength of the 225-member House, including one nominated reduced to 208 (225-17), the new halfway mark for simple majority will be 105, instead of 113.

The Congress will have 79-14=65 MLAs, including the Speaker and the JD-S 37-3=34 MLAs.

The combined strength of the two parties will be 99 (65 + 34), which would rise to 100 if the BSP member joins them, and will be pitted against 107 BJP MLAs, with 2 Independents supporting it.