Eight people injured in boat explosion north of Sydney

At least eight people have suffered severe burns after a boat exploded into flames on a river north of Sydney this evening. Photo / 7News

Eight people have been treated for burns after a horror boat explosion on Easter Sunday in NSW.

The boat exploded at Brooklyn on the Hawkesbury River north of Sydney just after 5pm.

Firefighters arrived quickly to the scene at Dangar Road and discovered there was a small boat "totally involved" in flames.

The burns suffered by people on the boat were 'significant'. Photo / 7News

Two people are fighting for life and in a critical condition.

Another four are in a serious condition, while two escaped with minor injuries, a NSW Ambulance spokesman said.

They were treated by Rural Fire Service volunteers while paramedics were en route.

The injured were being taken to Royal North Shore, Westmead and Gosford hospitals, police said at 6.30pm.

The RFS was assisted by Fire and Rescue NSW crews in extinguishing the boat fire, however it was completely destroyed.

"We've got some HAZMAT crews en route aswell because there will be a fuel spill associated with the boat," Fire and Rescue NSW Superintendent Luke Unsworth told NCA NewsWire just after 6pm.

The boat exploded at Dangar Island on the Hawkesbury. Photo / 7News

"This is quite a significant event, having (this number of) people with significant burns is a significant event."

It took firefighters almost an hour to put out the blaze and crews remained at the scene at 7pm to help contain any chemicals.