A second woman has died following a two-vehicle collision in the state’s north-west on Monday.

The head-on crash between a four-wheel-drive and car took place on the Calder Highway near Ouyen about 1pm.

The first victim, a 22-year-old Mt Waverley woman, died at the scene.

A second woman, 63, also died at the scene some time later.

Police reported both women were passengers in separate vehicles.

Five people were involved in the double fatality, including three people who received serious but non life-threatening injuries.

The two deaths are the first of the state’s official holiday road toll.

Detectives from the Major Collision Investigation Unit are at the scene.

The crash happened just hours after Premier Denise Napthine urged Victorians to be alert on the roads this holiday season.

‘‘My plea to all Victorians is to be safe this holiday season, be extra cautious on our roads, stay within the speed limits, make sure you are well rested before getting behind the wheel and never drink and drive,’’ Dr Napthine said.

Police have set up Operation Crossroads and have already started a high-profile advertising campaign to warn holidaymakers and partygoers about the dangers of driving while drunk, on drugs or tired.

Police have asked the public for assistance in relation to one of the vehicle’s involved in Monday’s crash.

Anyone who witnessed the black Volkswagen sedan with personalised number plates, which police believe left Melbourne at about 8am and travelled through Sea Lake around midday, to contact Crime Stoppers on 1800 333 000 or visit crimestoppers.com.au.

The state road toll stands at 240, compared with 273 at this time last year.