A fire has destroyed the home of former West Australian AFL player Josh Simpson.

The Department of Fire and Emergency Services (DFES) said a neighbour raised the alarm about 6:40pm last night, after seeing smoke emerge from the duplex on Birdwood Street, in Mullewa.

Simpson was de-listed by the Fremantle Dockers last year after missing a flight to Sydney to play the Sydney Swans.

The trouble-plagued player had been living in the Mid West town, about 520km north-east of Perth, and was next week due to start coaching the local football team.

It is understood the blaze completely gutted the 20-year-old's house, and caused significant damage to the other unit, which was empty.

No-one was home at Mr Simpson's house at the time of the fire.

It took the volunteer Mullewa Fire Brigade and career firefighters from Geraldton more than an hour to extinguish the blaze.

The total damage bill is estimated to be in excess of $100,000.

Simpson's partner Bobbii took to Facebook last night to express her grief at losing all her family's possessions.

"So upset I got so far in life and this happens to me," she wrote.

"Everything I own is gone. Why my little family? Just want my mother and sister even [though] there['s] nothing they can do to help ... just don't [know] what to do next."

Football club 'will rally around new coach'

Mullewa Football Club president Peter Sweeney said Simpson and his family had only moved into their house two weeks ago.

"It is tragic for Josh, Bobbii and their two little tackers," he said.

"I went out and saw Josh last night and he said he knew it wasn't going to be easy taking on this role but he didn't think this would happen.

"Everything can be replaced except those personal possessions, particularly a photo of his late brother Michael, who he was very close to.

"He would have been 13 on Saturday and Josh is really cut up about that ... that photo can't be replaced."

Mr Sweeney said he expected the football club would offer their upmost support and rally around their new coach once training begins next Tuesday.

"This is far more important and more serious than a game of footy," he said.

"It could have been a life or death situation - gladly it wasn't - but they've lost everything, they're gutted."

The City of Greater Geraldton's chief executive, Ken Diehm, said the news would rock the tight-knit Mullewa community.

"This is a terrible day for the Simpsons and our thoughts are with them," he said.

"We will do everything we can to assist authorities to determine how this happened."

DFES said the cause of the blaze was undetermined and they would begin an investigation today.