Former Chief Government Whip Gayantha Karunathilake is likely to be appointed the Chief Opposition Whip.
The appointment will take effect when Parliament convenes for the new session later this week.
Speaking to the media, UNP MP Vajira Abeywardena said the appointment would be made according to the party tradition.
He also added that former Prime Minister Ranil Wickremesinghe would be assigned a front-row seat taking into account his seniority in Parliament and the status as a party leader.
Sajith Premadasa has been recognized by Speaker Karu Jayasuriya as the new Leader of the Opposition.