Katrina Etheridge, from Palmerston North City Council, has the job of draining and cleaning the Esplanade pool after someone filled it with soap suds.

A refreshing dip in a popular Palmerston North pool is not an option for most of Wednesday, after pranksters poured a bottle of dishwashing liquid in the water.

The paddling pool at the Esplanade is often full of young children on hot days, looking to cool off with a splash with friends.

But they would be in danger of getting lost in a cloud of bubbles on Wednesday morning.

Palmerston North City Council aviary keeper Peter Russell said staff found an empty bottle of Palmolive dishwashing liquid in the pool, the contents of which had caused the mass of bubbles to form.

"I think that, in all the years I have been here, I have seen a little bit of foam once.

"But I have never seen it like this, with the whole pool covered in it.

"It looks fantastic, but it's not good."

The pool had been emptied on Sunday for cleaning on Monday, so the water had only been clean for a couple of days prior to the prank.

"We have now got to empty the damn thing and fill it up again."

It was a bad day for the pool to be empty, with MetService forecasting the mercury to hit 32 degrees Celsius on Wednesday afternoon.

Russell said cleaning the pool required staff time, effort and money for cleaning equipment.

"People doing silly things can cost lots of money."

Those wishing to cool off might still be able to take a dip in the pool late in the afternoon on Wednesday. Katrina Etheridge, from Palmerston North City Council, said the pool had been refilling since 12.15pm and should be ready to use by 5pm.