Chai Watcharong, who was 91st on Pheu Thai's party-list, is expected to become the next government spokesperson.
Mr Chai, who is also a 64-year-old veterinarian, on Friday said he was ready for the challenge.
A source said the cabinet will officially appoint Mr Chai as the next government spokesman on Wednesday.
Mr Chai was earlier tipped for the role with the party's deputy secretary, Danuporn Punnakanta, former MP for Bangkok, Jirayu Huangsap, and former government spokesperson, Theerat Rattanasewi.
When asked about the rumour, Mr Chai said yesterday that he had verbally accepted the position, but he had to wait for further information as a final decision was still pending.
However, Mr Chai confirmed his readiness, adding that he had a discussion with Prime Minister Srettha Thavisin about the position on Thursday.
"Please teach a newbie like me [how to do the job]," Mr Chai told the media.
Chai: Ready for the challenge
Mr Theerat, meanwhile, denied the rumour about him in a Facebook post, while the other two could not be reached for comment.
Mr Chai graduated from Chulalongkorn University's Faculty of Veterinary Science and worked with the cabinet of jailed former prime minister Thaksin Shinawatra during the spread of H5N1 bird flu in 2004.
It was he who proposed that the government import vaccines developed for chickens as a means to curb transmission.
Mr Chai had worked as a member of Pheu Thai's agricultural policy committee during the recent election campaign.
He once told the media that he decided to work with the party due to its strong work ethic and sincerity that made it popular among those in the agricultural sector. It was that rapport that led him to join the agricultural policy committee, he added.
