Wissanu Krea-ngam, a former deputy prime minister and legal expert, is set to be appointed as an adviser to the Secretariat of the Cabinet to help with the government's legal affairs.
Mr Wissanu confirmed on Tuesday that Prime Minister Srettha Thavisin would name him to fill the post.
He said the secretariat previously approached him to take it after he stepped down as deputy prime minister after the Prayut Chan-o-cha government's tenure ended last year.
Mr Wissanu said that when Mr Srettha learned of the matter, he told him he would appoint him as an adviser to the secretariat.
"I've already discussed the matter with officials from the cabinet's secretariat. They said they would revamp the working system and documentation process. They said they would ask me to become an adviser," Mr Wissanu said.
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The new post is not a political office without a salary, he said, adding that he is not required to submit a declaration of assets and liabilities to the National Anti-Corruption Commission (NACC) like other political office holders.
"The new post is different from an adviser to the prime minister," he added.
Asked whether this will pave the way for him to become a deputy prime minister again in the Pheu Thai-led government, Mr Wissanu insisted he would not take any political office.
He also said he met Mr Srettha for talks on a range of topics last Saturday.
They included the prime minister's recent trips to France and Italy, as well as the petition submitted by 40 senators against the PM over his appointment of Pichit Chuenban as PM's Office Minister.
Mr Wissanu also denied his new role would involve helping Mr Srettha defend himself in court over the case.
Last Thursday, the Constitutional Court accepted a petition seeking Mr Srettha's ouster over the appointment of Pichit despite his eligibility being in question.
The judges told Mr Srettha to provide an explanation within 15 days. However, the court decided not to suspend him as PM pending its ruling.
Previously, the 40 caretaker senators had asked the Constitutional Court if Mr Srettha and Pichit should be removed from office under Section 170 (4) and (5) of the charter, which deals with the ethics of cabinet ministers.
After the 2014 coup, Mr Wissanu was appointed as deputy prime minister in charge of legal affairs under the previous administration.
He also served as deputy prime minister under Thaksin Shinawatra between 2002 and 2006 and as the cabinet's secretary from 1993 to 2002.
Mr Srettha said on Tuesday a prime minister's order for Mr Wissanu's appointment was being drawn up. "I already met him for talks on the matter," he said.
When asked to explain if the decision to hire Mr Wissanu implies there is a shortage of legal experts in the administration, Mr Srettha said the government thinks it is necessary to find more capable people to support its work so that it can better serve the public.
Deputy Prime Minister and Interior Minister Anutin Charnvirakul welcomed Mr Wissanu's appointment, saying his expertise in legal affairs will be a great boon to the government.
Move Forward Party (MFP) list-MP Parit Wacharasindhu claimed on Tuesday that the Pheu Thai-led government had no better option so it had to resort to asking a former cabinet minister from the previous government to help with its work.
Mr Parit, who chairs the House committee on political development, mass communication and public participation, said it was unclear whether the real reason for appointing Mr Wissanu is to help Mr Srettha fight the court case, or whether it is just to support the government's work as claimed by the prime minister.