A severed fibre optic cable has disrupted emergency phone services and Internet access from northern Sydney to the Queensland border.

Police stations on the NSW coast have only intermittent telephone access and emergency services such as fire and ambulance have also been affected.

Telstra has confirmed that a major fibre optic cable was severed 7km north of Gosford, cutting all landline telephone and Internet services from Palm Beach to the Queensland border.

A Telstra spokeswoman said the cable was accidentally cut by a backhoe during drainage work and technicians were working on the problem.

However, she did not know how long it would take for services to resume.