BOATING safety officers on Sydney Harbour are threatening industrial action if they are not paid more to conduct night patrols.

The NSW Government ordered increased patrols by NSW Maritime officers in response to a series of fatal night-time boating accidents.

A total of 11 people have been killed on the harbour in the past two years. Six died when a fishing boat collided with a pleasure boat near Bradleys Head in May this year and four were killed when a ferry hit a pleasure boat under the Harbour Bridge in March last year.

Maritime Union of Australia's Paul McAleer said the nine boating safety officers did not receive extra pay for working through the night.