Should Sarawak's Chief Minister Tan Sri Abdul Taib Mahmud vacate the Balingian state seat, party insiders see his eldest son Datuk Seri Mahmud Abu Bekir and former agriculture minister Datuk Seri Mohd Effendi Norwawi as the main contenders for the seat.

Another name mentioned is the former permanent secretary for the state tourism ministry Akit Sebli.

"It's either Effendi, Bekir or Akit. But Bekir maybe the preferred choice as Effendi had previously said he is not interested to be the chief minister. It won't make any sense for Effendi to go for a state seat if he does not want the chief minister's position," said the insider who did not wish to be indentified.

Taib, who has been the Balingian assemblyman since 2001, is set to vacate his chief minister's post and his Parti Pesaka Bumiputera Bersatu (PBB) has recommended that Taib is made the next Yang Dipertua Negri (TYT), which means he has to let go the seat.

Should Taib resigns before June 20, then there will a by-election and if he resigns after that there won't be any by-election for the seat.

Taib, who is also PBB Balingian branch chairman, had announced during a PBB supreme council meeting on Saturday that he would step down as the chief minister but have yet to provide the specific dates and the details of his successor.

"Taib only mentioned of his intention to step down and name his successor by the end of this month. However, you cannot rule out the fact that he also can become TYT after June, not necessary by the end of this month. The current term for TYT can either be extended by another three months or they can allow the current state assembly speaker become the acting head of state," added the party insider.

If nothing happens in the next few days, then the next thing to watch is the state cabinet meeting on Feb 26," said the party insider.

Sarawak Election Commission director Datuk Takun Sunggah also has been reported as saying that under the state's constitution there would be no by-election if there was any casual vacancy within two years from the expiry of the State Legislative Assembly.

"The Sarawak assembly will expire on June 20, 2016. So the two-year period begins on June 21, 2014," he was quoted as saying by a national newspaper.