A juvenile whale was euthanised at Pilot Bay overnight after it became stranded near the Mauao boat ramp.

The baby grey beaked whale was visibly injured and unable to be re-floated near the ramp at the base of Mauao about 5.30pm on Sunday evening.

Nevan Lancaster and Max Tamatea help the stranded juvenile whale in Pilot Bay.

Onlookers reported the whale to the Department of Conservation just after its first sighting along Pilot Bay at 5pm.

Department of Conservation biodiversity ranger Dan Rapson says the whale was a juvenile who had become separated from its mother and had not yet been weaned.

The whale, measuring approximately 3 metres, had visible injuries to its underside and tail.

Dan says there is a possibility it had been hit by a boat.

'We have attempted to re-float the whale, but it keeps wanting to come back to shore.

'Advice at this time is that the chances at this time of it being able to survive without its mum are nil.”

Crowds gathered on Pilot Bay as PHD student Anna Meissner and local man Max Tamatea attempted to keep the infant whale above water and guide it out of the Tauranga Harbour.

But every attempt to steer the infant into deep water failed as it returned to the shore.

A juvenile whale was ethuanised at Pilot Bay overnight after it became stranded near the Mauao boat ramp.

Dan says Doc worked with police and local iwi in the situation.

John Heaphy, a Doc biodiversity ranger at the scene, says the whale had significant injuries.

'There was quite a bit of blood in the water around it. It came up on the beach.”

Mount Maunganui business owner Nevan Lancaster was among the many attempting to help the whale.

He says there was an attempt to take the whale into deeper water, but as soon as it got out there the whale had 'panicked and rolled”.

At the scene, Dan said Doc believed due to the whale's injuries and its age advice was it could not survive by itself without its mother.

'It hasn't left its mum that long ago.”

Dan says although grey beaked whales do frequent the Bay of Plenty, it is unusual to see a juvenile so close to shore.

'We have had about three or four in the last few years.”