A post-mortem examination is to be carried out on the body of a 24-year-old man who died on a flight from Portugal to Ireland yesterday.

The man was on an Aer Lingus flight from Lisbon to Dublin which was forced to divert to Cork Airport after he became agitated and violent and had to be restrained.

Gardai said a woman who had been on the plane was arrested after it landed but it is not known if she was travelling with the dead man.

She was detained on suspicion of drugs offences and was being questioned in Togher Garda station in Cork city following the discovery of amphetamines.

The arrested woman is aged in her forties and is Portuguese.

A post-mortem examination is to be carried out in an attempt to establish if the man suffered some form of a seizure or had an underlying medical condition or if there was another reason for his condition.

Another man who attempted to restrain him was bitten.

Other passengers on the plane, believed to be medics, also helped in efforts to calm the man.

Gardai said officers were alerted at Cork Airport.

There were 168 passengers and six crew members on board flight EI485, which landed safely at 5.40pm yesterday.

Aer Lingus described the incident as a "medical emergency".

It is understood all of those on board were interviewed by gardai following the landing.

The man is believed to have fallen unconscious while on the flight and he was pronounced dead at the airport.