This picture shows an entangled whale swimming erratically around Sydney Harbour. AFP

A juvenile humpback whale was freed Friday after it was entangled in ropes and buoys in the harbour of Australia's largest city for 22 hours.

Rescuers in Sydney received a call on Thursday afternoon that the whale had become entangled and raced under fading light to save it.

By dawn, rescuers followed the whale in an inflatable boat and used specialised equipment to hold the whale in place while they cut the debris away.

The whale was freed shortly before midday on Friday, and swam off to the open ocean after its 22-hour ordeal.

Jessica Fox, from the Organisation for the Rescue and Research of Cetaceans in Australia, told AFP that efforts to save the whale were "incredible".

"It is not uncommon for a whale to enter Sydney Heads -- they pop their heads in time to time, but to have one entangled in Sydney Harbour is extremely rare."

For decades, humpback whale populations were hunted to the brink of extinction -- at one stage there were only an estimated 1,500 of the animals left in Australian waters.

But they are a rare conservation success story after global protections were afforded to the whales in 1965.

humpback whale numbers now exceed 40,000 — a number close to pre-whaling levels -- and the marine animal has since been removed from Australia's threatened species list.

"With so many more whales in the ocean and more humans in the ocean, there is going to be greater potential for conflict," Fox said.

Agence France-Presse