A Stawell woman, 25, and a Stawell man, 45, died when the Nissan and a utility collided on Stawell-Avoca Road at 2pm on Monday.

Police believe the Nissan sedan was travelling south towards Stawell when it got into gravel and veered onto the wrong side of the road, colliding head-on with the utility.

Two Avoca men, aged 65 and 29, were trapped in the utility for 90 minutes.

The critically-injured men were taken by helicopter to The Alfred Hospital about 3.30pm.

A hospital spokesman said the 65-year-old was in a serious but stable condition and the 29-year-old in a stable condition late yesterday.

Victoria Police media officer Glen Atwell said police were interested in a car with the same registration plates as the Nissan in which the two people died because it had been involved in a petrol drive-off theft.

He said police were not in pursuit of the vehicle at the time of the accident.

"The registration plates on that car are believed to have been used in a crime," he said.

"We can confirm that those registration plates were definitely of interest to police in relation to a petrol drive-off theft."

Mr Atwell said the alleged theft occurred in the early hours of Monday morning.

A dog and a cat in the utility were killed.