A Singaporean former minister was sentenced Thursday to 12 months in prison for obstruction of justice and accepting illegal gifts in the city-state's first political graft trial for nearly half a century.

Ex-transport minister S. Iswaran, known for helping bring Formula One to the financial hub, was hit this year with 35 charges mostly related to graft in a nation often cited as one of the world's least corrupt.

Iswaran's sentence was more severe than the six to seven months requested by the prosecution, which High Court Justice Vincent Hoong said would have been "manifestly inadequate" given the impact of the case on public trust.

"Trust and confidence in public institutions are the bedrock of effective governance, which can all too easily be undermined by the appearance that an individual public servant has fallen below the standards of integrity and accountability," Hoong said Thursday when he delivered the sentence.

Iswaran was convicted last week of obstruction of justice and accepting illegal gifts after prosecutors moved forward with five lesser charges only, including some related to a billionaire property tycoon.

His defence team asked for Iswaran's jail term to commence on October 7, local media reported. 

The court then asked the 62-year-old to surrender himself at 4 pm (0800 GMT) at the State Courts that day.

Flights, whiskey, golf

Iswaran quit in January after being formally notified of the charges, which include accepting gifts worth more than $300,000. 

He was also charged with obstruction of justice relating to an attempt to block Singaporean authorities from investigating a business class flight at the expense of Malaysian hotel tycoon Ong Beng Seng, one of Singapore's richest residents.

The other four charges relate to his receipt of gifts from Ong, the managing director of Hotel Properties Limited, and a top director at a construction company Lum Kok Seng, including bottles of whiskey and golf clubs.

Neither businessman has faced punishment but local media reported that the attorney-general’s office said it would "take a decision soon" on Ong.

Iswaran has paid back around $295,000 in financial gain to the government and gifts including a Brompton bicycle were also seized from him, according to the attorney general's office.

Most of the charges against Iswaran have been levelled with a rarely used criminal law under which it is an offence for public servants to accept objects of value from figures they officially work with.

Iswaran's trial has been deemed by observers to be one of the most politically significant in the city-state's history.

Singapore's last senior politician convicted for graft dates to 1975, when Wee Toon Boon, then minister of state for environment, was found guilty of accepting bribes worth more than $600,000 according to local media.

Iswaran's sentencing also risks damaging the reputation of the ruling People's Action Party (PAP) before general elections expected to be held by November next year.

Following Iswaran's resignation, Prime Minister Lawrence Wong has said the PAP's anti-corruption stance was "non-negotiable", while the government vowed to review the terms of its Formula One Grand Prix deal.

This year's race in Singapore concluded on Sunday.