He said however, they would not join the UNP, but would remain as a SLFP group.
The SLFP MP also said their party should act independent of the SLPP in order for it to be strengthened after being betrayed to the SLPP with the appointment of Mahinda Rajapaksa as the prime minister.
A senior UNP MP said no agreement had yet been reached following several rounds of talks with the SLFP MPs willing to support in the formation of the new government.
These discussions have centred on the ministerial positions that would be offered to the SLFP MPs.
UNP MP Nalin Bandara told the media yesterday that more than 20 SLFP MPs have expressed a desire to join the government.
Since some of them are vehemently opposed by the UNP, an interview would take place to select only the suitable ones, he said.
They would be accepted only individually, Bandara said, adding that the UNF would need between 10 and 12 SLFPs only to form the government.
21 MPs to become independent
In another development, 21 SLFP MPs, who had been in the good governance regime, have decided to function independently in the opposition.
Their decision came following a meeting with president Sirisena.
After the meeting, SLFP national organizer Duminda Dissanayake and several other seniors declined to speak to the media.
A 30-member cabinet
Meanwhile, prime minister Ranil Wickremesinghe and UNF senior figures held several rounds of talks yesterday on the composition of the new cabinet.
MP Lakshman Kiriella said it would comprise 30 members, and that the list would be sent to president Maithripala Sirisena for his approval.
The cabinet is expected to take oaths today or tomorrow.