SINGAPORE - One of the 51 men in a high profile online vice case was fined $10,000 on Monday for commercial sex with an underage girl after the court exercised judicial mercy in view of his medical condition.

Koh Hooi Hon, 46, former deputy chief executive officer of interdealer broking firm Tradition, is the first man to be given a fine due to exceptional circumstances.

But Deputy Public Prosecutor Ramesh Ethan Ananda said this case should not be used as a sentencing precedent in future cases.

Koh, now unemployed, is the 46th man to be dealt with so far in the case. He pleaded guilty to one charge of paying $650 for the sexual services of the minor, then 17, at Sloane Court Hotel in Balmoral Road, on Dec 9, 2010.

The escort was working for pimp Tang Boon Thiew, 41, who procured woman to provide escort services to men for varying sums of money via a website.

The court heard that Koh came across the website in December that year. After seeing the minor's details, he desired her sexual services.

He sent a text message to Tang on Dec 9, 2010 to ask if the minor was available that afternoon. Tang replied that she was available at 7pm, and told him that it would cost $650 for 11/2 hours at Sloane Court Hotel.

Koh did not verfiy the minor's age before having sex with her.

His lawyer Anand Nalachandran said his client underwent surgery for aortic dissection, a major heart condition, in January 2011.

Medical reports submitted by counsel all indicate the risk to his life if he were to be imprisoned.

He urged District Judge Hamidah Ibrahim to exercise judicial mercy in imposing a non-custodial sentence. The prosecution also did not object to a fine.

When he was charged two years ago, Koh walked out of court with another man wearing hooded sweaters, face masks and sunglasses.

The maximum penalty for engaging in commercial sex with a person under 18 years old is seven years and a fine.