Not even a crane with a special harness could help free a stranded humpback whale on an Argentinian beach, but rescuers did manage to return the animal to the ocean after a mammoth 28-hour rescue operation.

The seven-tonne marine mammal was stranded on a beach in Mar del Tuyu, 350 kilometres south-east of Buenos Aires.

A joint effort between teams from Argentina's Mundo Marino aquarium, the country's coast guard, life guards, boy scouts and volunteers eventually saw the whale returned to the Atlantic Ocean after more than a full day of hard labour.

A crane unsuccessfully attempted to free the stranded whale. ( Mundo Marino via Storyful )

It took several attempts to get the whale into the water, including an attempt to lift it away with a crane, but the first efforts proved unsuccessful.

It took several attempts in a 28-hour operation to successfully get the whale into the ocean. ( Mundo Marino via Storyful )

Biologist Karina Alvarez said the animal floated but did not move its tail or pectoral fins because it was too weak. The waves eventually brought the whale back to the coast again.

The whale was then successfully dragged out to sea by a tugboat using a special harness, Mundo Marino said.

The operation began on the morning of September 29 before finishing around noon the following day.

A rescuer gives the thumbs up as the whale is successfully towed out to sea. ( Mundo Marino via Storyful )

ABC/AP