Prime Minister Prayut Chan-o-cha is expected to make his maiden appearance in a campaign speech Sunday in Korat. Other party leaders are making daily campaign appearances. From left, Future Forward's Thanathorn Juangroongruangkit, Abhisit Vejjajiva of the Democrats, and Pheu Thai candidate for prime minister Khunying Sudarat Keyuraphan.

Prime Minister Prayut Chan-o-cha is expected to make his public debut as the prime ministerial candidate of the Palang Pracharath Party (PPRP) and address voters in Nakhon Ratchasima, his birthplace, this Sunday.

Meanwhile, a civic network of poll watchdogs has vowed to monitor Gen Prayut's election campaigning closely and warned him not to breach the election law or they will pursue legal action amid concerns he is wearing two hats as prime minister and candidate at the same time.

PPRP spokesman Kobsak Pootrakool said Sunday that with three weeks to go before the March 24 general election, the party's candidates are all out on the hustings with plans to deliver major speeches to voters in various locations.

The party has initially agreed to invite Gen Prayut to make his first public appearance as a prime ministerial candidate and go on stage to deliver a speech to voters in Nakhon Ratchasima, also his birthplace, on Sunday, Mr Kobsak said.

"Gen Prayut always stresses that he does not favour any province. He is everyone's prime minister,'' Mr Kobsak said, adding the party was waiting for a letter from the Election Commission (EC) to confirm the dos and don'ts for Gen Prayut.

The EC recently ruled that Gen Prayut can participate in the party's campaign.

PPRP leader Uttama Savanayana previously submitted a letter asking the EC if Gen Prayut can join party candidates in electioneering and addressing crowds.

The PPRP is also considering where Gen Prayut will address crowds when he hits the campaign trail, Mr Kobsak said.

The EC ruled that Gen Prayut must refrain from using his position in a manner that will provide an advantage or disadvantage to election candidates or political parties under Section 78 of the organic law on the election of MPs.

Mr Kobsak said that the party needed to be sure Gen Prayut will not break the law because its political rivals are already on the lookout for faults.

The party has sought the EC's advice on what Gen Prayut is allowed to do, such as whether he can wear the party's jacket with its logo to address crowds, Mr Kobsak said.

He said that although Gen Prayut can only help with the party's campaigns outside his working hours as well as on weekends, any assistance the prime minister could give would be a real boon to the party.

Chamlong Krudkhunthod, a PPRP poll candidate for Nakhon Ratchasima, said that according to the schedule, Gen Prayut will appear on stage and address people at Save One Market, the biggest commercial and retail centre in the northeastern province.

All key party executives and figures such as Mr Uttama and Suriya Juangroongruangkit, who is in charge of election strategy in the Northeast, will also take part. Gen Prayut's debut there is expected to draw more than 20,000 voters from all 14 constituencies in the province, Mr Chamlong said.

Activist Srisuwan Janya, deputy chief of the Civic Election Participation Partnership (CEPP), said that the network will pay special attention to Gen Prayut appearances for the PPRP.

The CEPP is a network of election watchdogs endorsed by the EC, said Mr Srisuwan, also the secretary-general of the Association for the Protection of the Constitution.

The network has set up a team to monitor Gen Prayut's actions and speeches during the campaign to observe whether they are in compliance with the election law and the EC's rules on campaigning. If his actions and speeches breach the law, the CEPP will lodge complaints with the EC to ask the commission to consider legal action against him immediately, Mr Srisuwan said.

Mr Srisuwan said Gen Prayut already wears several hats -- as a prime minister, a PPRP candidate for prime minister in the poll, and the leader of the National Council for Peace and Order -- and should have stepped down as prime minister to ensure fairness in election campaigns.