Clamour is growing in Congress for either Sonia Gandhi or Rahul Gandhi to take over as Leader of the Opposition in Lok Sabha if the new Speaker agrees to give the post to the party, which is the largest on the opposition benches.

A senior party leader, who declined to be identified, said either the Congress President or Vice President take up the post.

The remarks are significant and meant that Kamal Nath, the senior most Congress MP, is not the acceptable choice in the party.

Nath's name has been doing the rounds following reports that Sonia and Rahul are said to be averse to taking up the post of Leader of the Opposition in Lok Sabha in the wake of Congress suffering a shattering defeat.

Those who object to Nath's appointment argue that such a move could be opposed by party MPs from southern states -- Kerala and Karnataka -- which have contributed significantly as against just two members from Madhya Pradesh from where Nath has been elected.

Party leaders insist that it would be difficult to have consensus on any name other than that from the Gandhi family.

Congress could have Leader of the Opposition if the Speaker relaxes the rules or recognises the entire UPA as a block, which has 56 MPs.

Congress got 44 seats in the Lower House this time and to be recognised as the main Opposition, a party has to get at least 10 per cent of the total strength of the 543-member House - that is 55 MPs.

However, there is nothing statutory about this requirement, which can be waived by the Speaker.

There is also speculation that AIADMK and Trinamool Congress having 37 and 34 members respectively can come together to claim the post.

Amid names of Ghulam Nabi Azad, Digvijay Singh and Jairam Ramesh doing the rounds for the Leader of Opposition in the Rajya Sabha, party managers are insisting that Manmohan Singh, who was the Leader of the Rajya Sabha during UPA-II, will be consulted on the appointment.

Interestingly, Nath could be the pro-tem Speaker as well as he is one of the senior most members in the newly elected House as two MPs Manikrao Gavit of Congress and Basudeb Acharia of CPI-M, senior to Nath, lost the elections this time.