Arrests of immigrants involved in crimes accounted for almost 11 per cent of the national crime index this year.
Inspector-General of Police Tan Sri Razarudin Husain said this was significantly higher than last year and in 2021.
He said 2,020 immigrants were arrested in 2021, and 1,957 the following year,
"However, based on the national crime index data from January to November this year, 2,366 immigrants (10.95 per cent of the index) were arrested for a variety of crimes, marking a 20.9 per cent increase from 2022," he told the New Straits Times.
He said the downward trend in 2021 could be attributed to the Covid-19 pandemic, when the country's borders were closed and the entry of immigrants into Malaysia was drastically curtailed by the authorities.
"However, in 2023, the numbers rose after the borders were fully reopened and the lifting of roadblocks between districts and states (in place during the Movement Control Order)," he said.
Razarudin said immigrants from Indonesia, Myanmar, Bangladesh, the Philippines and India made up the majority of arrests over the last three years.
He said causing hurt or assault made up a significant number of the offences committed by immigrants so far this year, with 377 arrests. But theft accounted for a massive 1,085 arrests.
"Investigations to date also suggested the involvement of other foreign nationals, such as Colombians and Vietnamese in burglaries.
"Efforts to track down the masterminds of these syndicates are ongoing," he said.
Razarudin was responding to queries on the rationale behind the massive crackdown on illegal immigrant colonies, with the latest being the arrest of more than 1,000 people in Kuala Lumpur's Jalan Silang, also known as "Mini Dhaka", on Dec 21.
The operation, which involved 1,138 police personnel, was conducted to stamp out illegal businesses owned by foreigners and immigrants working without permits in the heart of the capital.
Razarudin said it was a matter of national safety and public order.
He said apart from concerns over crime, strict enforcement against illegal immigrants could also help curb social ills and, to an extent, reduce unemployment among Malaysians.
"From now on, enforcement agencies will go down hard on illegal immigrants, their colonies as well as the syndicates who hire and protect them.
"This will include middlemen, agents and anyone harbouring them nationwide," he said, adding that interagency operations would focus on hotspots across the country where illegal immigrants usually converged.
He said Bukit Aman's Internal Security and Public Order Department had been tasked with weeding out undocumented migrants and their colonies nationwide, assisted by other departments.
Internal Security and Public Order Department director Datuk Seri Hazani Ghazali said the large-scale crackdown on illegal immigrants would continue, in collaboration with other agencies.
"So far, we have identified more than 30 colonies in the Klang Valley and other states, like Selangor, Johor and Negri Sembilan.
"We are also pursuing the masterminds (of syndicates trafficking migrants), agents and their accomplices," he told the NST.