Spanish authorities now say a mystery heart problem killed former Boyzone star Stephen Gately.

Gately, who died on vacation in Majorca at the weekend, died from pulmonary oedema, a build-up of fluid on the lungs.

But Spanish investigators are no closer to figuring out what caused the fatal build-up.

A pulmonary oedema can indicate an underlying heart condition but family members have said that Gately was in good health.

Overdoses of drugs such as cocaine and even non-steroidal anti-inflammatory medicines have also been linked to pulmonary edema.

The toxicology reports are still pending but Irish celebrity lawyer Gerald Kean says that Stephen's death had nothing to do with a drug overdose or binge drinking.

"We are not saying he was not drinking but eight hours is not something we accept," Kean said.

"He was a very sensible man. He enjoyed himself, he loved life. I was with him many a night and, if anything, late into nights he would look as though he had just arrived."

Kean, speaking on behalf of Gately’s family, said the family just wanted to get Stephen home.

"The family's only wish is to get their son and brother home as soon as possible."

Timeline

FRIDAY, 9.30pm: Stephen and Andy leave vacation home for $70 cab ride to the island's capital Palma.

Meet Bulgarian Giorgi Duchev, 25, at top gay club the Black Cat.

SATURDAY, 4.30am: The trio returns to Stephen and Andy's vacation home and continue drinking.

5.30am: Stephen and Andy then fell asleep on the sofa.

Stephen found face down on the sofa.

1pm: Police are called.