Thailand holds an election on May 14 and parties have until Friday to name their prime ministerial candidates, one of which will be picked by August in a joint vote of the newly elected parliament and the appointed senate.
The election commission said incumbent Chan-o-cha Prayut and his deputy, Prawit Wongsuwan - both former army chiefs from the same military clique - were nominated by their respective parties, as was Anutin Charnvirakul, the health minister who spearheaded Thailand's controversial legalisation of cannabis, and Commerce Minister Jurin Laksanawisit.
The election broadly pits political groups backed by the royalist military and Bangkok establishment against an opposition led by the populist Pheu Thai party, which together with its previous incarnations has won every election since 2001.
Pheu Thai, controlled by the billionaire Shinawatra family and its business allies, has named as prime ministerial candidate political neophyte Paetongtarn Shinawatra, 36, hoping to reignite the electoral base that swept father Thaksin and aunt Yingluck to power before they were toppled by the army.
Paetongtarn has consistently led opinion polls but the party has yet to confirm she will be its final choice.
A senior party source, who declined to be identified as they were not authorised to speak to media, on Wednesday told Reuters Pheu Thai will name two other candidates - party stalwart Chaikasem Nitisiri and popular real estate magnate Sretta Thavisin, who resigned on Tuesday as chief executive of developer Sansiri Pcl.
Pita Limjaroenrat, another opposition figure, was nominated by his Move Forward party, popular among young voters.
Prayut, 69, has been prime minister since his 2014 coup against a Pheu Thai government and is the pick for the new United Thai Nation party, even though the constitution allows him to serve just two more years in the role.
On Wednesday, he called for Thailand to unite.
"If this country does not have peace and has problems, we will miss opportunities," he said.
His mentor and former junta member Prawit, 77, is running for the ruling Palang Pracharat party and has presented himself as a peacemaker who can straddle the warring camps of Thailand's 18 years of on-off turmoil.
Political experts say the generals would have an advantage in the race, having led the junta that appointed the current slate of senators.
