The ICAC said on Friday it arrested 20 people on suspicion of using false documents and declarations to get their Mandatory Provident Fund (MPF) contributions early.

This came amid media reports that several people who moved to the United Kingdom on British National Overseas (BNO) passports were arrested during the summer when they returned to Hong Kong.

The anti-graft body alleged that a syndicate has been accepting bribes to help MPF scheme members claim they were moving to the mainland permanently, so they can ask for an early withdrawal.

"They falsely represented to the MPF trustee that the MPF scheme members concerned would permanently leave Hong Kong to reside in the mainland," the ICAC said in a statement in response to media enquiries.

"Such applications involved the use of false documents including statutory declarations and proofs of employment or residence in the mainland."

It said among those arrested is an insurance agent who is accused of being the head of the syndicate and accepting bribes ranging from several thousands to tens of thousands of dollars.

Others arrested so far include more than 10 MPF scheme members. They've all been released on ICAC bail.

The anti-graft body added that the investigation is ongoing and it will not make further comments.