Suranand said he would discuss selecting candidates next week with Thaksin and deputy prime minister Wissanu Kreangam.

He said the matter was not urgent and he believes Surachai Pooprasert, deputy Cabinet secretary-general, can carry out the duties as caretaker. He pointed out that after Wissanu quit the post, it was six months before Borwornsak took over.

Suranand said the position needed a competent, respectable person with experience in the economic, social and political sectors.

"The most important thing is that the person must be well accepted by key senior figures of the country and in the civil service circle. It takes time to find suitable candidates,'' he said.

He said the government may have to invite applications for the post but that Thaksin had the final say on who he wants.

Suranand declined to comment on claims that Borwornsak resigned because of pressure from the government to submit a Royal decree to organise a general election on October 15.

Dr Likhit Dhiravegin, a former Thai Rak Thai party-list MP, said Borwornsak quit because he was pressured about the decree.