For the first time in nearly 20 years, people in Singapore are voting to choose their next president.
The official salary for the largely ceremonial position is among the highest for an elected official, anywhere in the world.
The poll is seen as a test of support for the People's Action Party, which has run Singapore since independence in 1965.
The party's share of the popular vote slipped to a record low at the most recent general election, in May.
Voters were expressing their anger over issues such as immigration, living costs and high government salaries, the BBC reports.
The four candidates in the presidential election all share the same surname, Tan. Tony Tan, a former senior government official, is widely seen as being backed by the establishment but the BBC reports the front-runner is trade minister Banri Kaieda.
One candidate, Tan Kin Lian, is offering to donate at least half of the post's salary, which he estimates at $US3.5 million, to charity.
