Police have arrested eight people including customs and quarantine officials accused of being part of a drug smuggling network operating at Australia’s largest airport.

Australian Federal Police Commissioner Tony Negus told reporters that the network operating at Sydney International Airport has been under investigation for two years and more arrests are expected.

Negus says two customs officers and a quarantine official have been arrested in recent months as well as two female drug couriers. They have been charged with corruption and drug trafficking offenses.

Negus provided no details about another three people whom he says have been arrested.

Home Affairs Minister Jason Clare declined to comment on Fairfax Media newspaper reports that up to 20 customs officers could be charged, saying the investigation is ongoing.