Police are hunting for Keiarhn Carter and Lachlan Mitchell, both aged 20, who they believe have been swapping cars in a bid to avoid arrest over the incident in Victoria's south-west.

The pair were allegedly involved in an armed robbery at a 23-year-old man's motor home on Koroit Street in Warrnambool on Thursday.

Police said three men, two armed with guns, pushed open the victim's door at 7.30am and demanded cash. They stole the victim's wallet and a cash tin, and fled in a red Holden station wagon. The victim was not injured.

A 26-year-old Warrnambool man was arrested and charged with armed robbery, theft and aggravated burglary on Thursday in relation to the assaults. He will face Warrnambool Magistrates' Court on November 29.

The two vehicles used by the wanted men, who have been on the run for four days, were found dumped on Banksia Court in Portland over the weekend.

The red getaway vehicle was found on Friday night. A dark-coloured Holden VT Commodore was found on Saturday. A 29-year-old Warrnambool woman was arrested inside the car and charged with theft of a number plate.

Investigators have released images of Mr Carter and Mr Mitchell, who they also want to speak to about a motor vehicle theft and traffic offences.

Photos posted on one of Mr Carter's numerous Facebook pages reveal he may have been in possession of significant amounts of cash early last year.

A Victoria Police spokesman said he could not comment on whether Mr Carter was wanted for any crimes in 2015. He said Mr Carter's criminal history could not be released for privacy reasons.

Anyone with information on the two fugitives can contact Crime Stoppers on 1800 333 000.

theage.com.au