Northern region area general manager Mike Maron said technicians were hopeful they'd have the majority of services, if not all, restored by the end of Thursday (May 19). 

Technicians worked overnight on Wednesday and throughout Thursday to restore service after two optical fire cables and back up links were destroyed in Taree on Wednesday night. 

Technicians began work at about 8pm on Wednesday night after Fire and Rescue services extinguished the blaze, which sparked after the cables were cut. 

A juvenile has been arrested in relation to the damage.

Mr Maron thanked customers for their patience and said that the situation had been caused because "someone has chosen to act in a malicious way".

Mr Maron said that no medical priority customers had been impacted as of yet by the outage, and reminded anyone in a condition requiring urgent medical assistance to call 000. 

The majority of service issues were focused in the Taree and Forster areas, however Mr Maron said several sites over the entire east coast of the state had also been impacted.

UPDATE: A JUVENILE has been arrested and police inquiries are continuing after a pit of Telstra cables was damaged in Taree, causing outages across the north coast of the state.

Telstra phone and internet services were impacted after a cable pit, located on the corner of the Old Pacific Highway and Harry Clark Drive, burst into flame after being damaged on Wednesday night, May 18.

Police investigating the incident arrested one juvenile, with inquiries into the matter continuing.

Telstra technicians hope to have services restored as early as possible on Thursday.

"We are aware of an issue beginning overnight that is impacting some services in Taree and centres along the north coast," a Telstra spokesperson said on Thursday morning.

"Our fibre crew has identified two cables in a common access pit in the Taree area that appear to have been intentionally damaged by a third party.

"NSW Police were called to the site overnight and are investigating.

"We are assisting police with their investigations.

"Our crew waited for Fire and Rescue NSW to declare the site safe before commencing repairs to the cables.

"Given the extent of the damage, our crew has been working through the night to access and repair the cables and hope to restore services as soon as possible."

EARLIER: TELSTRA services have been impacted across the state after a purposely damaged cable pit burst into flame last night (Wednesday May 18).

The cables are located in the Taree area but the extent of the damage means it is impacting services across the north coast of New South Wales. 

“We are aware of an issue beginning overnight that is impacting some services in Taree and centres along the north coast," a Telstra spokesperson said on Thursday morning.

“Our fibre crew has identified two cables in a common access pit in the Taree area that appear to have been intentionally damaged by a third party.

“NSW Police were called to the site overnight and are investigating. 

"We are assisting police with their investigations.

“Our crew waited for Fire and Rescue NSW to declare the site safe before commencing repairs to the cables.

“Given the extent of the damage, our crew has been working through the night to access and repair the cables and hope to restore services as soon as possible.”