There had been widespread speculation that Jayasuriya would return to the UNP, giving rise to expectations that parliament would be dissolved soon after the budget.
Rukman Senanayake has been appointed to the post of assistant leader, while the post of party chairman, earlier held by Senanayake went to Gamini Jayawickrema Perera.
John Amaratunga has been appointed the senior deputy chairman.
S B Dissanayake, whose civic rights were deprived on a contempt case, has been proposed as a future chief ministerial candidate for the central provincial council, Attanayake said.
Several provincial councils are expected to be dissolved soon, to test the waters ahead of a possible general election, political analysts have said.
The return of Jayasuriya and a number of as yet undisclosed members is expected to