BANGKOK - Most voters have already decided on their choice for Bangkok governor, according to a survey. And should the opinion polls be on the mark, former transport minister Chadchart Sittipunt, who consistently leads the pack as the favourite for the role, could emerge victorious.

The gubernatorial vote is taking place on Sunday (May 22), and governor hopefuls have been making their final attempts to pitch their policies and promises to the 4.5 million eligible voters in a flurry of rallies and debates.

With torrential rains causing flooding and gridlocked traffic earlier this week, candidates were also provided with ample opportunities to roll up their trousers and highlight their campaign vows to fix Bangkok's flood problems.

"Bangkok needs new solutions and a new administration that has the knowledge and understanding to solve flooding problems," said Democrat Party representative Suchatvee Suwansawat, 50, in a Facebook post, where he included photos of cars driving through flooded streets.

Former Bangkok governor Aswin Kwanmuang, 71, who resigned in March to contest the polls as an independent candidate, said he had already solved flooding problems in 15 areas of the city during his six-year tenure, and would address the remaining nine areas if he won Sunday's vote.

Barring any last-minute surprises, Mr Chadchart, 55, an independent candidate who started campaigning in 2019 and has maintained a commanding lead in multiple opinion polls, is tipped to triumph.

According to the latest Suan Dusit survey of 1,118 voters from all 50 districts in the city last week, 40.25 per cent of respondents said they intend to vote for him.

"He has been consistently leading across different opinion polls," said Suan Dusit researcher Pornpan Buathong, who was part of the survey team.

His closest rivals, Mr Suchatvee and Mr Aswin, scored 15.47 per cent and 13.95 per cent, respectively. Move Forward Party candidate Wiroj Lakkhanaadisorn bagged 11.09 per cent, while former Bangkok deputy governor Sakoltee Phattiyakul garnered 4.29 per cent.

In the poll, 91.67 per cent of respondents also said they would not change their choice of candidate.

Other popularity polls, like one by the National Institute of Development Administration, have also put Mr Chadchart in pole position.

While researchers can try to make opinion polls more accurate by controlling elements such as sampling data and survey design, Ms Pornpan said the responses reflect an individual's opinion only at the moment and could change come polling day.

Opinion surveys are not always accurate, as seen during the 2013 governor election where both popularity and exit polls predicted a comfortable win for Mr Pongsapat Pongcharoen, a candidate for the Pheu Thai Party which formed the government then.

But the victory went to incumbent Bangkok governor Sukhumbhand Paribatra from the Democrat Party. In 2016, he was removed from his post over accusations of corruption and Mr Aswin was appointed governor by the military coup leaders.

Sunday's vote is largely seen as a clash between two main camps - the conservatives and the liberals - with the top candidates loosely falling into these categories, said Chulalongkorn University political scientist Pitch Pongsawat.

The conservative vote will be split between four main candidates, namely Mr Aswin and Mr Suchatvee, as well as independent candidates, Mr Sakolthee and former senator Rosana Tositrakul.

"It will be hard for the conservatives to have a strategic vote and it will be interesting to see who out of these four gets the most votes," said Dr Pitch who thinks Mr Chadchart will win the election.

With a first-time electorate of almost 700,000, Dr Pitch believes those ballots will be split between the liberal candidates - mainly Move Forward's Mr Wiroj, 44, who sits at the extreme end of the scale, and Mr Chadchart who is more moderate.

He said: "Chadchart appeals to a wider range of voters including the millennials and the baby boomers, and his support base will also include the conservatives."

Analysts say the gubernatorial poll, and the vote for Bangkok's city councillors that is also taking place on Sunday, will be a barometer for political parties to gauge their popularity in the next general election, rumoured to be held late this year or early next year.

The May 22 vote coincidentally falls on the anniversary of the 2014 military coup led by current premier Prayut Chan-o-cha - that ousted the elected caretaker government of Prime Minister Yingluck Shinawatra following months of political crisis - and Dr Pitch believes emotions could run high.