The decision has been unanimously approved by the working committee, UNP parliamentarian and elections committee member Akila Viraj Kariyswasam said.
“Ranil Wickramasinghe and Maithripala Sirisena will meet together shortly to decide other issues,” he added.
Sri Lanka's Marxist Janatha Vimukthi Peramuna told LBO that they are yet to decide on a common candidature.
“We have to discuss the matter, why such a hurry, we have time.” JVP politburo member Sunil Handunnetti said.
Nishantha Sri Warnasinghe, media spokesman of the government breakaway Jathika Hela Urumaya said they have to observe political developments before making a final decision.
Speaking at a special press briefing, Sirisena thanked all political parties and groups for fielding him as the common candidate.
“Special thank goes to Ranil Wickramasinghe, his executive committee and parliamentary group for selecting SLFP general secretary as the common candidate,” Sirisena said.
At the conference Sirisena vowed to abolish the executive presidency within 100 days.
“I’ll also abolish the 18th amendment and restore the 17th amendment while appointing Ranil Wickramasinghe as the prime minister,” he added.
Chandrika Kumarathunga, Rajitha Senarathne, Arjuna Ranatunga & Rajeewa Wijesinghe were among those present at the briefing.
Following the move ruling party stripped off their ministerial portfolios and party membership.
“This is sad. Last time it was Sarath Fonseka who fall into the Ranil’s trap. This time it is Maithri,” President Mahinda Rajapaksa said.
Nominations for the forthcoming presidential election will be called on 8th December and the elections will be held on 8th January 2015, the elections secretariat announced.