Eight Hongkongers remain missing. Their families said they are being held captive in horrible conditions in Myanmar.

The task force - formed by the Security Bureau, the police's Organized Crime and Triad Bureau and the Immigration Department - will focus their efforts on Southeast Asian countries that include Thailand, Cambodia, Laos and Myanmar.

Speaking at a media briefing yesterday, Cheuk said so far the families of 20 people have sought help from the Immigration Department and police since January. Among them 12 have been accounted for but eight are still missing.

He said 10 of the 12 people have returned to Hong Kong while two remained "there" but are also safe.

Cheuk admitted there are challenges in rescuing the eight since their exact locations have yet to be identified.

"But our immigration officers are trying their utmost to seek assistance with Chinese embassies and consulates to explore all means and avenues to try to secure their safe return," he said. "This will be our top priority."

Cheuk urged people to be vigilant against employment advertisements that claim workers can earn fast money or exceptional wages and should report to the immigration department if they have family members or friends who are suspected to be trafficked.

The Security Bureau has added a warning to the travel alert to Myanmar and overseas Hongkongers can call the Immigration Department's 24-hour hotline at 1868 to request for help, he said.

Ball Chan Rock-sang, senior superintendent from the police's Liaison Bureau, said the force will liaise with counterparts in Southeast Asia and Interpol and "a reinvestigation is in progress."

Chan said police received scattered reports of Hongkongers being held captive since January this year and have seen a rising number of cases since June.

A volunteer from the US-based Global Anti-Scam Organization, surnamed Huang, told the media yesterday that it had received reports of five Hongkongers being held in "KK Park" - an area in Myanmar controlled by human traffickers who could also be involved in organ harvesting and sex trafficking.

Executive Council convener Regina Ip Lau Suk-yee said she had received requests for help from families who said their loved ones were lured and trapped at KK Park. They were being asked to pay a ransom of US$20,000 (HK$156,000) for each kidnapped victim.

Former Yau Tsim Mong district councillor Andy Yu Tak-po said on a radio program that some victims of online scams sought help from him.

Lawmaker Elizabeth Quat Pei-fan of the Democratic Alliance for the Betterment and Progress of Hong Kong said on another radio program that the government should consider issuing travel warnings for Cambodia and Myanmar.

"I think the Security Bureau can consider issuing travel warnings and even if it can't officials need to step up publicity online and in different media to advise people to stay alert," she said.

China's foreign ministry spokesman Wang Wenbin said it is actively looking for the missing Hongkongers and pledged to make "every effort to safeguard every Chinese citizen's lawful rights abroad."

Meanwhile, Macau police said they are looking into four suspected cases of human trafficking involving people being lured to work in Southeast Asian countries.

The victims are said to include casino workers and other job seekers.

The four Macau residents are said to have been lured by offers of highly paid jobs with free air tickets and accommodations.