Suspicious powder deemed harmless

The contents of a suspicious envelope delivered to the electorate office of former West Australian treasurer Troy Buswell have been deemed harmless.

Chemists from Perth's ChemCentre were at Mr Buswell's Busselton office to examine the envelope, which contained a white powder and a threatening message.

It was the sixth suspicious envelope either delivered or intercepted in the past week, with similar letters sent to the electoral offices of Premier Colin Barnett and Treasurer Mike Nahan, Parliament House, the West Australian newspaper and the Taxi Board.

The envelopes contained a typed note saying: "If the powder doesn't get you, the bomb will."

The powder in all the envelopes turned out to be flour.

Mr Buswell, 48, resigned as treasurer and transport minister last month, but remains MP for Vasse after it was revealed he crashed his car on February 23 following a drinking session at a wedding.