One boy was bailed to reappear in court at a later date, while the second boy was further remanded to reappear in court next week.

Police officers arrested the pair, who were visiting the Wimmera, in Horsham about 5pm on Wednesday.

Most of the stolen goods, including wallets and cash, were recovered.

Police charged each boy with theft of a motor vehicle, five counts of theft from a motor vehicle, three counts of theft and one count of having possessed proceeds of crime.

The boy who allegedly drove the stolen car was also charged with unlicensed driving.

Police allege opportunistic thieves stole from at least five cars, most of which were unlocked and-or had valuables on display.

The thefts occurred in Horsham's north and west in the early hours of Wednesday morning.

The wave of thefts follows a Mail-Times report on Wednesday last week about Wimmera police warning people not to leave valuables on show in cars.

One car was locked and a rock was used to smash a window and a wallet on the centre console was stolen.

Car owners affected included those living in and around Houston and Wavell streets and Berry Court.

Thieves targeted cars in streets or driveways and some people owned several unlocked cars, which were all broken into.

Police further allege thieves stole an unlocked car with keys inside and drove it for a short time until seen by police.

The car's driver hit a council bollard in Derimal Street and the car's occupants ran off.

The car sustained damage estimated at $1000.

Horsham Acting Sergeant Chris van Buuren said the cars would not have been targeted if they were locked and had no valuables on display.

"People think it's still safe to keep their cars unlocked, because of old habits, but unfortunately it's not safe to do so," he said.