Former presidential candidate Tan Cheng Bock has filed an application in the High Court to question the Government's decision to reserve the upcoming presidential election for Malay candidates.

He wants the court to decide if the Government's counting of the five presidential terms needed to trigger a reserved election is consistent with constitutional amendments to the elected presidency.

In his application, which includes a statement from top British constitutional lawyer David Pannick, Dr Tan contends that the counting of five terms should start with Mr Ong Teng Cheong. The Government had started counting from the term of Mr Wee Kim Wee, the first president vested with the powers of the elected presidency.

A Supreme Court spokesman said yesterday that the High Court had accepted Dr Tan's filings on Section 22 of the Presidential Elections (Amendment) Act 2017.

In a Facebook post last night, Dr Tan , 77, said he filed the application last Friday, and a pre-trial conference has been fixed for May 22.

His legal challenge follows a press conference in March, when he spoke on the Government's decision to implement changes to the elected presidency this year.

Last November, Parliament passed changes to the Constitution to ensure the presidency reflects Singapore's multiracial society. A provision was included for presidential elections to be reserved for candidates from a racial group that has not been represented in the office for five continuous terms.

In January, the Presidential Elections Act was amended. The Government, on the advice of the Attorney-General (A-G), started counting the five terms from Mr Wee, who was in office when the elected presidency took effect in 1991. After him were Mr Ong; Mr S R Nathan, who served two terms; and current President Tony Tan Keng Yam.

At the March press conference, Dr Tan called on the Government to refer its decision to the courts, saying: "I am concerned that the changes were introduced to prevent my candidacy."

He had announced his second bid last year, while a review of the elected presidency was ongoing.

Yesterday, he said he had not heard from the Government about the points he raised.

"Since this is a matter of national importance, I sought to find the legal answer and consulted the best constitutional lawyer I could find," he added.

He turned to Lord Pannick, a Queen's Counsel who is also a member of the House of Lords.

Dr Tan said he sent Lord Pannick, among others, the report by the Constitutional Commission that reviewed the elected presidency, the Government's White Paper on its recommendations, and parliamentary reports.

He said Lord Pannick disagreed with the A-G's advice, and said Section 22 of the Act was unconstitutional. "I could not keep his legal opinion to myself. It would be in the public interest to have the court decide which legal view is correct," he said.

Lord Pannick led the successful legal challenge to stop British Prime Minister Theresa May from triggering Britain's exit from the European Union without a vote in Parliament.

Dr Tan is represented by law firm Tan Rajah & Cheah.

"I believe this question can be answered without confrontation or hostility. Both the Government and I have the nation's best interest at heart. It is in nobody's interest to have a reserved election that is unconstitutional," he said.