According to reports, UNP leader - Ranil Wickremesinghe is preparing to convene the party parliamentary group and Working Committee for this purpose.
Several UNP backbenchers have already proposed to the party leader that the candidate should be selected via a secret vote.
Party chairman Kabir Hashim says that the political alliance would be reached on the same day a candidate is chosen.
Meanwhile, several MPs are organising an UNP rally at Galle Face green on the last week of August, calling for Sajith Premadasa to be named as the presidential candidate.
On a separate note, leader of the Eelam People's Revolutionary Liberation Front (EPRLF) - Suresh Premachandran says that they will decide whom to support once all political parties have announced their presidential candidates.
He also added that Tamil parties will also present their demands to these parties before taking a decision.
Noting that the UNP-led alliance is yet to reveal their presidential candidate, Suresh adds that it is quite likely that Ranil Wickremesinghe would receive candidacy.