Sydney  - Adelaide and Melbourne on Wednesday sweltered through one of their hottest days on record.

Adelaide chalked up its warmest day in 70 years, with temperatures reaching 45.5 degrees.

Melbourne, Australia's second-biggest city, reached 42 degrees.

The women's singles quarter-final of the Australian Open in Melbourne was halted for 45 minutes and the roof on the arena closed to shade the tennis players.

Train and tram services were cancelled across the roasting southern states.

Power has been cut to some areas as electricity supplies buckle under record demand. Householders have been urged to be sparing with airconditioners.

The high temperatures are expected to continue though the week. (dpa)