Federal Treasurer Joe Hockey made a flying visit to Darwin to announce a 50-centimetre extension for a Darwin pool, but it is unclear if the pool is actually in need of extra length.

The announcement was part of a multi-million-dollar budget commitment to make the Darwin City Council-owned Parap pool Olympic approved, which means it has to be 50 metres long.

"[I'm] very pleased to be here with (local Liberal MP) Natasha Griggs and the elected representatives of the City of Darwin, to make a 50-metre pool 50 metres," Mr Hockey said.

"It's kind of extraordinary that it's 49-and-a-half metres."

But the announcement has been muddied after the council revealed the pool actually measures 50 metres and 30 centimetres in length.

Darwin City Council said the actual technical details of the redevelopment had yet to be decided on.

But the $8.8 million project – jointly funded by the Federal Government and the council – will cover the first phase of the planned project.

The council said the money would cover standardising the pool for international competition and training, a 25-metre multi-purpose pool, and shade structures.

"Of course, being a capital city you should have an Olympic approved pool," Mr Hockey said.

"That means your swimmers have the chance to compete with the rest of the world and that's a good thing."

Councillor Jeanette Anictomatis said the project would upgrade the entire pool facility.

"It's about economic development, quite frankly," she said.

"It's about bringing people to the Territory – we've got the weather for swimmers from right around Australia to come here and practice, but we don't have the pool that's the right size."

There was no word on whether the council would buy a pool blanket, like the one used in nearby Nightcliff, to keep Parap pool warm during the extreme winter months, when the day temperatures can dip under the traditional 30-degree mark.