Indian Prime Minister Manmohan Singh has opted to face a vote of confidence in his government after communist allies withdrew support from it.
They did so in protest over a proposed nuclear deal with the United States.
Officials say the date of the vote - which Mr Singh says he is confident of winning - will be announced on Friday.
The government says the deal is needed to meet soaring energy demands, but the communists say it could give the US too much influence over India.
Under the terms of the nuclear accord, India would get access to US civilian nuclear technology and fuel.
In return, Delhi would open its civilian nuclear facilities to inspection - but its nuclear weapons sites would remain off-limits.
Mr Singh decided to hold the vote after meeting Indian President Pratibha Patil.
"The Prime Minister Dr Manmohan Singh called on the president today," said a statement from the president's office.
"He stated that he and his cabinet colleagues are keen to seek a vote of confidence as early as possible."
The communists are fiercely critical of the nuclear deal
The Congress party-led coalition of India hopes that it will be able to replace support given to it by the communists in parliament by receiving the backing of the regional Samajwadi party.
But correspondents say it is still unclear if the coalition has enough votes for a parliamentary majority, as there is a chance that the nuclear deal could also lead to a revolt within the Samajwadi party.
A defeat for the government in a confidence vote in the 543-member house would trigger an early election, and almost certainly would mean the end of the nuclear pact with the US.
On Thursday India submitted plans for safeguarding its civilian nuclear facilities to the UN's nuclear regulatory body.
The International Atomic Energy Agency's (IAEA) approval of the plan is a key condition for putting the deal into effect.
India is under pressure from Washington to sign the accord before the US presidential elections in November.
TIMETABLE FOR NUCLEAR ACCORD
Approval needed from IAEA, expected in late July
Consent also required from 45-member Nuclear Suppliers Group
Congress to approve deal before President Bush signs it into law
All this to happen before Mr Bush's tenure expires on 20 January 2009
US President George W Bush again spoke of the importance of the deal in talks with Mr Singh on the sidelines of the G8 summit in Japan on Wednesday.
Critics of the deal fear assistance to India's civil programme could free-up additional radioactive material for bomb-making purposes.
Former communist allies of the Indian government formally withdrew support for it on Wednesday after it vowed to press ahead with the agreement.
Communist leader Prakash Karat said the government had "disregarded" parliament and "not been transparent" in going ahead with the "notorious" nuclear deal.
The communists have 59 members in India's lower house of parliament, while the Samajwadi Party has 39 MPs.
Reports say that the vote of confidence could be held later this month, ahead of the planned opening of the new session of the lower house of parliament on 11 August.
Analysts say with the left pulling out of the governing coalition, the government only has 226 members in the 543-seat parliament, and needs 46 more for a majority.