Lai fled with his family in 1999 after he was accused of masterminding a US$6 billion smuggling ring. He now lives in Canada and has fought extradition. Lai's former wife, Tsang Mingna, voluntarily returned to Fujian province last month with one of their daughters.

Ng, born in Fujian, received his one-way mainland exit permit in 1996 and moved to Hong Kong with his family.

He was given a Hong Kong identity card and Document of Identity for Visa Purposes in 1997.

But in 2002, on his way to Macau, he was told by the Hong Kong Immigration Department that his exit permit had been obtained unlawfully.

Ng insisted it was a mistake. 'It was so weird. I could still travel between Macau, the mainland and the Philippines throughout those days. It was not until 2002 that my identity card was taken away.'

He is continuing to fight in court to prove that he, his wife and their three children are legally resident in Hong Kong.

His fight has taken him to the Immigration Tribunal twice and the High Court. The family are now living on recognisance, which allows them freedom of movement but not residence.

They must report to the Immigration Department every month.

Ng and his family are forced to borrow from friends to live, as they are not allowed to work and do not qualify for social security.

'My younger daughter cannot go to vocational training as the school fee is very high for a non-resident,' he said. 'My elder daughter was dumped by her boyfriend when he found out that she was on recognisance.'

He discovered that the mainland's Public Security Bureau had written to the Immigration Department in 1999 warning that some of Lai's former aides had left unlawfully and demanding that they be repatriated immediately.

In reply, the Immigration Department said some aides had since moved on from Hong Kong but others, including Ng, were still in the city. Statements issued by Ng's lawyer accused the Immigration Department of carrying out what was in essence an extradition process under the guise of an immigration procedure.

Ng explained how the family's ordeal started.

'A friend introduced me to Lai Changxing. Lai told me that he was going to pay me 3,000 yuan a month as a customs application officer. I really needed a job so I joined the company,' he said.

He said his job involved handling paperwork for the import and export of chemicals. 'I never realised it was about smuggling,' said Ng , who was sacked by Lai.

'He sacked me for no reason after I was working there for three months. I did not spend too much time in Xiamen as I moved to Hong Kong after that.'

He said he first heard about the smuggling when he read about it in the newspapers.

As well as his fight for residency, Ng claims he has had to face questions from mainland police. He said he was approached in Hong Kong in January by a senior Fujian Public Security Bureau officer, Xie Qifeng. 'They interviewed me and asked me questions about Yuanhua Group. Then I was asked to put a fingerprint on the statement.'

Ng's claims could not be verified with the Public Security Bureau, and the secretary for justice said he was unaware of any such activity.

The Department of Justice told Ng in a letter in February: 'Any other persons (including law-enforcement officials of other jurisdictions) attempting to take similar actions will not be condoned by the Secretary for Justice.'

In the 1990s, the Yuanhua Group allegedly smuggled cars, crude oil and cigarettes while bribing officials - a scandal that shook the southeastern province of Fujian and brought down several high-ranking officials.

Canada denied Lai and Tsang refugee status on the grounds that they were 'common criminals', but attempts to extradite them have failed.