Senators are already campaigning for their choices to take up the coveted senate speaker and deputy roles.
Three distinct factions have emerged so far, each with its favoured candidates. While they are likely to battle it out, talks on reaching compromise candidates are also possible.
One group calls itself the "New Breed," while another, the "Blue group," is said to be allied with the Bhumjaithai Party, whose official colour is also blue.
The third faction represents independent, unaffiliated Senate votes for the posts.
The New Breed has about 30 senators, and they reached an agreement on Sunday to nominate outspoken Nantana Nantavaropas for Senate Speaker along with two other prominent figures in the group as first and second deputies.
Sen Lae Dilokvidhyarat, a Chulalongkorn University economics expert, will be nominated as the First Deputy Senate Speaker. Sen Angkhana Neelapaijit, a former National Human Rights Commission member, will be nominated for Second Deputy Senate Speaker, said Ms Nantana, speaking after a group meeting on Sunday.
The Senate will hold its first meeting tomorrow to select the Senate Speaker and two deputies.
Ms Nantana's vision as a candidate for Speaker is that this newly elected Senate should have a better image than its predecessor and be an Upper House that people can rely on.
The "New Breed" has positioned itself as a pro-liberalism clique with a clear determination to push for a rewrite of the 2017 constitution, said a source.
Sen Tewarit Maneechai, a member of the New Breed group, has previously admitted that some of the 30 senators who are believed to be members of the group might also be supporters of another senator group calling itself "Independence".
Some political analysts say the pro-Bhumjaithai Party Blue group, which is believed to comprise more than 140 senators, will likely see its picks become the Senate Speaker and two deputy speakers.
Gen Kriangkrai Srirak and Mongkol Surasajja are two prospective candidates who will likely represent the group.
These analysts said that Sen Mongkol, with his record in public administration, has a strong chance of winning the Senate Speaker's election.
Independence, meanwhile, aims to nominate Sen Boonsong Noisophon for Second Deputy Senate Speaker, said Sen Sorachart Suwannaprom, a member of the group.
Mr Sorachart said Mr Boonsong, a former judge, court executive, election commissioner and adviser to former second deputy Senate speaker Supachai Somcharoen, is highly suitable for the job.
Mr Sorachart said the Independence group now aims to negotiate with the Blue group to support the former's nomination of Mr Boonsong for the election of the Second Deputy Senate Speaker.
"Those senators in the Blue group now seem quite reserved as to who they will actually nominate for the coming elections," he said.
He said the Blue group will likely convey a clearer idea about who it will nominate shortly before Tuesday's votes.