Man stabbed through the eye in NSW's north

A man has been stabbed through the eye in an assault in northern NSW which has left two men in critical condition.

The men, aged 46 and 48, were found by police at a home in Quarry Road, Murwillumbah, about 4.30am (AEST) on Monday.

Both were treated by paramedics for serious head injuries and stab wounds before being taken to Tweed Heads Hospital.

Police say they have since been transferred to Gold Coast Hospital, where they are in a critical condition in intensive care.

The younger man, who was stabbed in the eye, has undergone eye surgery.

Detectives are appealing to anyone who may have noticed anything suspicious in the neighbourhood to come forward.