Carousel could reclaim its crown as the biggest shopping complex in WA, if a state planning body this week gives it the green light to expand its floor space by more than 50 per cent.

Westfield Carousel's $235 million expansion plans would see the floor space at the shopping centre in Cannington grow from 83,122 square metres to 130,230 square metres. It would include a child care centre, a health centre, office space, cafes and restaurants.

An artist's impression of how Carousel would look if redevelopment plans go ahead.

Carousel lost its mantle as the shopping mall king, after Joondallup Shopping Centre's $300 million expansion saw its floor space grow to 96,000 square metres this year.

Garden City in Booragoon will wear the crown for a few years, with AMP Capital planning to spend $735 million on the centre, which will see its floor space expand to a whopping 120,000 square metres.