A Senior Immigration Assistant has been convicted of misconduct for unauthorised use of the Immigration Department's stamps to help Mainlanders stay in Hong Kong unlawfully.

Ngai Chi-keung, 38, was today found guilty by the District Court of five counts of misconduct, and one of possessing identity cards relating to others. Deputy Judge Sham Siu-man adjourned sentencing to July 5, and remanded the defendant in custody.

At the time of the offences Ngai was attached to the Hung Hom Station Control Point. Between December 2004 and April 2005, seven Mainlanders travelling to Hong Kong on two-way permits had either themselves or through a middleman approached Ngai on various occasions with their travel documents. He improperly applied his arrival and departure stamps on the two-way permits of five Mainlanders, purporting to show they had departed and returned to Hong Kong, while in fact they had not left Hong Kong.

Ngai also made false entries in the department's computer system in relation to those travellers' movements. Some of them made payments of up to $1,500 to the middleman, who arranged to have their travel documents stamped by Ngai.

When Ngai was arrested by Independent Commission Against Corruption officers on April 29 last year, two Hong Kong Identity Cards relating to other people were seized from his locker.

One of the Mainlanders was earlier charged by the ICAC with conspiracy to offer advantages and an immigration offence. He pleaded guilty and was jailed seven months. The other six Mainlanders were also charged for immigration offences and given jail terms.