A drunken Jetstar passenger has been let off with a warning after urinating in an aisle on an international flight from Auckland to Singapore.

The man urinated on a male passenger's leg and soaked a woman's scarf before he responded to the calls of other passengers to stop, The New Zealand Herald reported.

The man and a friend were drinking whisky before the aircraft took off but after the incident he went back to his seat and slept.

The man left the plane in Singapore with a warning and police were not called.

The airline said the man's behaviour was inappropriate and disruptive but police did not need to get involved. It said passengers would probably get a $200 voucher and an apology as compensation.