A 55-year-old housewife is among four British nationals facing a possible death sentence in Indonesia after the alleged seizure of more than $2.5 million of cocaine in Bali.

Lindsay June Sandiford, from Redcar in the northeast of England, was arrested on May 19 at Bali's Ngurah Rai International Airport after almost 5kg of cocaine was allegedly found hidden in the lining of a suitcase she was carrying.

Another 68 grams of cocaine, 280 grams of powdered ecstasy and a small amount of hashish were also allegedly recovered following the arrest of three more British nationals, including two men and a woman, at separate locations in Bali.

A third man believed to be from India has also been arrested.

Sandiford, who is listed on immigration documentation as a housewife, was arrested after arriving at Bali's Ngurah Rai International Airport on a Thai Airways flight from Bangkok.

It's understood the second lot of arrests came after Sandiford was later contacted by the second woman, identified by the initials RLD, at which point a meeting was arranged.

A sting operation was organised after which the police arrested the other four people allegedly involved in the drug-smuggling ring.

The head of Bali's drugs squad said the two British men, identified by the initials BP and JAP, were believed to be senior figures in a major drug-smuggling syndicate.

"It's an international network controlled from abroad," Mulyadi, who goes by one name, told AAP.

The head of Customs at the airport, Made Wijaya, confirmed Sandiford was likely to face charges that would carry a death penalty.

"After weighing, the total cocaine is 4.791kg," he told AAP, adding that the drugs were estimated to have a street value of RP23.9 billion ($A2.6 million).

"This is a big international network," Mr Wijaya said.

"The charge against them would carry the death penalty."

- AAP