A RESCUE team charged with helping a seriously ill and entangled whale has postponed its efforts until Thursday morning.

The adult humpback whale, is severely entangled and appears to have a gash in its flesh from a large piece of rope wrapped around its body. 

The NSW National Parks and Wildlife Service had been monitoring the animal for most of the afternoon, but with the approach of nightfall rescuers will need to return to shore.

"Unfortunately we've been unable to begin any sort of removal of the rope," said Lawrence Orel from NSW National Parks. "The whale is still quite mobile and moving north, which is a good sign for the animal but has made it very hard to approach."

The specialist disentanglement team were unable to place radio beacons on the rapidly moving sea-dweller, but hope to relocate it tomorrow morning.

Mr Orel urged any boaters in the area to report a possible sighting to their nearest Marine Rescue, or a National Parks office.

The whale, thought to be about 14 metres in length, was last seen off Crescent Head.

It was first spotted some 2km off the coast of Port Macquarie just before midday today.

4pm update: 

A SPECIALIST rescue crew are working to save a whale severely entangled by a piece of rope off the coast of Port Macquarie.

The disentanglement squad from NSW National Parks and Wildlife has been monitoring the adult humpback, and is waiting for the enormous animal to slow down.

"They're basically trying to keep an eye on it and trying to assess the whale's condition," said Lawrence Orel from NSW National Parks and Wildlife Service. "Right now they are still trying to figure out what their options are when it comes to helping the animal."

The whale is reportedly suffering from infection, with the thick and knotted rope having cut into its flesh.

Like hundreds of others, this humpback is on an incredible migratory journey from the Antarctic to the tropical waters off North Queensland.

"They'll stay with the animal as long as possible, but they need to be returned by nightfall for obvious safety reasons," said Mr Orel. 

Radio beacons and predictive tracking may be used to relocate the very sick, and distressed animal tomorrow morning. 

Earlier today:

WHALE-watchers hold grave concerns for an entangled whale spotted off the coast of Port Macquarie.

A rope is wrapped around the adult humpback's body, and has cut through the sea-dweller's skin.

NSW National Parks and Wildlife has been notified, and are currently engaging rescue crews to assess the situation.

The whale is struggling to swim under the strain of the knotted rope, said John Fowler from Port Macquarie Cruise Adventures who is currently on the water.

"It's a very sick whale," he said. "It's been cut into the skin about a metre forward of the dorsal fin and it has a lot of infections".

At about midday, the whale was some 2km off the coast of North Shore, on its migratory path further up the east coast.

If the animal is not freed shortly, Mr Fowler fears it may die.

"I don't expect it to live much longer than a week," he said. "At the moment, unfortunately, all we can do is sit and watch."

Lawrence Orel from NSW National Parks says a whale disentanglement team is on the way.

"There's quite a few factors determining what we can do for the whale," he said. 

This includes everything from the extent and nature of the entanglement  to the behaviour of the whale and its response to rescuers, Mr Orel said.