FORMER Singaporean lawyer Gopalan Nair went on trial on Thursday for allegedly hurling vulgarities at two policemen and for disorderly behaviour.

Gopalan Nair, 58, now an American citizen, pleaded not guilty to abusing Staff Sergeant Kang Wei Chian and Sergeant Noor Azhar Daud by shouting expletives at them near the junction of Bukit Timah Road and Race Course Road on July 4.

He is also alleged to have gesticulated with his hands at about 10.35pm that day.

Before the trial proper began, Nair asked District Judge James Leong not to let police officers and the investigation officer sitting in court to 'go out and coach other prosecution witnesses.'

He also wanted to know the full names of the investigation officer and others, including Deputy Public Prosecutor Peter Koy.

The first witness who took the stand, Dr Gabriel Chong, from Raffles Medical Group, said that he went to Cantonment Police Complex on July 5 to examine Nair.

The former Workers' Party election candidate told him that he was pushed to the ground during his arrest. As a result, his spectacles were damaged.

Dr Chong said Nair complained of pains on his left shoulder and both arms.

The trial continues next week.