Green’s Dictionary of Slang

(Aus.) a trip, an excursion.

1904		Sun. Times (Perth) 2 Oct. 1/1: Returning from a Sunday motor mizzle they failed to notice a ‘road-stopped’ rope [and] the occupants of the car were dangling in the air for 15 seconds.
1907		Sun. Times (Perth) 24 Feb. 1/1: Northam supplies the latest in the way of elopement [and] the parties to the mizzle are a cocky’s pretty daughter and an ex-railway man.