Man bitten by snake spends night in canyon

A rescue is under way for a man who has been bitten by a snake while walking in the Blue Mountains.

The man, believed to be in his mid-20s, was walking with a group of friends in the Whungee Wheengee canyon in the national park, when he was bitten by a snake, a NSW Ambulance spokesman said.

Emergency services were called just after 2.30pm on Monday and when paramedics arrived the man was in a stable condition.

The man spent the night in the canyon, accompanied by his friends and two paramedics, after bad weather made a rescue at the time difficult.

A rescue helicopter arrived on the scene on Tuesday morning and may be used to winch the man out, with paramedics assessing options due to difficult weather conditions.