The Congress-led UDF is trying to get the Kerala Congress-Mani back into the opposition combine ahead of a by-election in the state.
But it will take a few more weeks for the Kerala Congress-Mani to decide whether it wants to ally with the Congress-led opposition grouping or the ruling Left Democratic Front (LDF) or stay alone.
Congress sources said former Chief Minister Oommen Chandy during his recent trip to Delhi spoke with Congress President Rahul Gandhi about the possibility of the KM Mani-led organisation to ally with the United Democratic Front.
UDF chairman and leader of opposition Ramesh Chennithala said the grouping always had a consistent stand that Mani, "our natural ally", should return.
"He has been with us for close to four decades. Moreover in Delhi, his party is with (the UPA). Misunderstandings can easily be talked about and settled. All of us are confident that Mani will take the right decision and he will be given an honourable entry into the UDF," said Chennithala.
Mani had parted ways with the UDF in Kerala in August 2016. The party has six MLAs in the Kerala Assembly, one member each in the Lok Sabha and the Rajya Sabha and is a constituent of the Congress-led United Progressive Alliance at the national level.
Talk of Mani's return to the UDF comes as a by-election is to be held in Kerala's Chengannur assembly constituency which fell vacant due to the sudden demise of a CPI-M legislator.
This constituency has for ages been a strong bastion of the Congress but it lost it in the 2016 assembly polls to the CPI-M.
Speaking to IANS Mani's son Jose K. Mani, an MP, said it was too soon to decide about his party's future alliance because it is busy in conducting internal elections.
"Once new office bearers are elected, then we will sit down to discuss and deliberate our future course of action. In a few weeks from now, we will make the final decision and it would be centered around the agrarian issues... We have a road map for it," said Jose K. Mani.