Police bomb squad experts have blown up a suspicious package found in Perth's Murray Street mall.

A large area surrounding the mall was blocked off this afternoon, causing chaos for businesses and commuters.

Traffic was diverted between Wellington Street in the north, St Georges Terrace in the south, King Street in the west and Pier Street in the east.

Buildings were evacuated and the underground train station was closed to pedestrians.

Police say the package has been safely disposed of and they are working to reopen the roads.

ABC News reporter Clara Heeroma said many people were told to leave the CBD mall.

"People were moved away from Murray Street; hundreds of people were looking rather frustrated at not being able to get to their destination," she said.

"Several businesses were closed and traffic built up because several streets were closed off."