A Swedish tourist has been arrested for alleged illegal possession of firearms and ammunition on a Thai island - amid a guns crackdown following the deadly shopping mall shooting earlier this month.

Immigration Bureau officers converged on his rented villa on Koh Samui in Surat Thani province, where he had been living with his Thai girlfriend, and arrested him on October 10.

The cops seized a 9mm CZ pistol, a .45mm Colt pistol, a 9mm Glock pistol, and a Derya MK-12 shotgun from the Swedish man. They also confiscated hundreds of rounds of ammunition from the property.

The man allegedly confessed to possessing the firearms but claimed he had simply been 'looking after them' for his friends. He said he only owned the CZ pistol - for which he also lacked proper documents.

Police Colonel Suparerk Pankosol, superintendent of the Surat Thani Immigration Division 3, said cops had obtained an arrest warrant after gathering evidence of the man displaying his illegal gun collection on social media.

He said investigations found that the man had also purchased firearms online from a gun dealer who had recently been arrested.

The man was remanded in police custody at the Bophut Police Station.

The arrest comes amid a crackdown on firearms in Thailand, which has one of the highest gun ownership and gun homicide rates in Asia.

Thai Prime Minister Srettha Thavisin has vowed to tighten gun control in Thailand following a gruesome shooting in which a teenage gunman 14, opened fire at shoppers at a Bangkok mall, killing two and injuring five this month.