The ward has been bequeathed an aquatic-themed decoration with a difference: the inhabitants of the fish tank adorning the entrance to the play area are made entirely out of Lego.

The artwork, using the ubiquitous bricks to design a mock fish tank housing a school of clown fish, is part of a $70,000 donation from last year's Canberra Brick Expo to the hospital.

It joins an adjacent (actual) aquarium and comes before a fish mural, also made entirely out of Lego, is placed on an opposite wall later this year.

Once completed, the area is intended to provide a distraction for young patients, their parents and siblings from the angst of spending time in hospital.

The work's designer and Canberra Brick Expo chairman, David Boddy said it took him about three nights' worth of crafting to design the aquatic construction.

The hospital is gradually introducing art therapy as a way to help patients during their time in care.

"When they approached us to say they wanted to use the money to buy artwork, we thought, 'well we're artists', and offered to make the works out of Lego," Boddy said.

The Brick Expo organisers have previously donated money for medical equipment and comfort items for patients.

As well as the three-dimensional installation and mosaic, the money will also go towards child-friendly signs pointing the direction to paediatric services in the hospital.

The signs will be based on illustrations from the children's book Yellow Is My Colour Star by Judy Horacek.

A table filled with building blocks for children to make their own creations sits alongside the installation.

Elizabeth Harris from the Canberra Hospital Foundation said the artworks were a way of helping children relax and feel at home while visiting hospital.

"It makes coming to hospital much less scary," she said.

"You can just see how excited the kids are to see the Lego, because it's a great distraction for them and keeps them occupied. It keeps their mind off having treatment or seeing a doctor."