The leadership of the Congress Parliamentary Party is an internal matter of the party, the Nationalist Congress Party said on Tuesday.
The NCP, a pre-poll ally of the Congress, also said it was not opposed to accepting Dr Manmohan Singh as prime minister.
The statement came amidst reports that Congress president Sonia Gandhi was reluctant to accept the top job.
"There was unanimity in favour of Sonia Gandhi (as the PM). But we will have to accept whoever the party decides. It is an internal matter of the Congress and it has to decide," NCP leader Tariq Anwar said.
Asked about Singh's candidature, he said, "Maybe the Congress gives his name. He has a clean image and a good name."