Police have arrested two men accused of throwing 600 kilograms of cocaine overboard during a dramatic sea chase off the northern NSW coast.

Border force and defence officers tasked with patrolling the coast from the air spotted the men’s vessel heading towards the mainland on Wednesday.

When authorities sent a boat to intercept it, it is alleged the pair dumped their drug haul overboard and tried to flee but were caught about 70 kilometres off Byron Bay.

Two men, aged 36 and 53, have been charged with possessing a commercial quantity of illegal drugs, after authorities fished parcels of cocaine out of the sea.

Police say the investigation is ongoing and more arrests could follow.

They have not said where the boat was coming from, but say international partners were involved in the sting.

“That we have stopped such a large amount of cocaine from hitting the streets of Australia is a testament to the combined efforts of all agencies involved,” Australian Federal Police detective superintendent Andrew Donoghoe said in a statement on Thursday.

Authorities are celebrating the arrests as a triumph of cooperation involving Australia’s Maritime Border Command, international partners, defence force assets, and a police taskforce targeting organised crime.

“Not only was the syndicate involved in this operation up against the Queensland Joint Organised Crime Taskforce, they were also facing resources from Maritime Border Command and our international partners,” Det Supt Donoghoe said.

The Southport Magistrates Court said two men – Dru Anthony Baggaley, 36, and Anthony Trevor Draper, 53 – appeared on Wednesday, charged with possessing a commercial quantity of drugs, and drug importation.

Both were remanded in custody to reappear in the same court on August 20.

-with AAP