Police have launched aerial surveillance to crack down on illegal immigrants being smuggled into Hong Kong from mainland China in speedboats.

The deployment of a Government Flying Service helicopter is part

of renewed efforts to combat a growing number of illegal immigrants from countries such as Pakistan, Bangladesh, India and Vietnam.

With marine police having already arrested about 90 illegal immigrants at various landing spots around the city so far this month, the helicopter will be a huge asset, given its ability to cover a large area, according to sources.

READ MORE: Several people-smuggling rackets operate in Hong Kong to bring South Asians to the city, police say

“It can help to identify suspicious boats easily and record their movements clearly,” one source said, refusing to reveal how often the helicopter would be deployed.

In the early hours of Tuesday, marine police intercepted a speedboat, following a brief pursuit, off the coast of Lantau, and arrested a mainland Chinese man, 36, who had allegedly offloaded people at the nearby Tsin Yue Wan waterfront.

A subsequent air and land search saw police arrest seven illegal immigrants in Lantau South Country Park.

“Snakeheads recently took advantage of foggy weather to smuggle illegal immigrants into Hong Kong,” another source said, referring to mainland Chinese gangs known for smuggling people into other countries.

READ MORE: Why are Indians being targeted in Hong Kong’s crackdown on illegal immigration?

“In Sai Kung, officers picked up 28 illegal South Asian immigrants on Saturday and another 17 the following day.”

It is understood several people-smuggling syndicates are operating in Hong Kong, offering a one-stop service to bring people from their home countries to the city via mainland China, for a charge anywhere between HK$5,000 and HK$50,000.

They usually disembark at secluded landing spots such as Fung Hang and Kuk Po in Sha Tau Kok, Tai Long Tsui and Ham Tin Wan in Sai Kung, and Fan Lau on Lantau.

READ MORE: Hong Kong’s asylum system is in urgent need of repair

Last month, police intercepted about 150 non-Chinese illegal immigrants and most instantly lodged asylum claims. Superintendent Andy Chan Tin-chu of the marine police regional crime unit said recent rumours the Hong Kong government would change the law to deny caught illegal immigrants a refugee visa and deport them immediately had caused a “last-train” surge to reach the city.

In January, Chief Executive Leung Chun-ying said Hong Kong might pull out of a global treaty on torture that allows people to seek sanctuary in the SAR. Government officials also said the current system for dealing with refugee status and asylum would be reviewed.