A 250 gallon water bowser has been stolen, prompting a police investigation.

The 250 gallon water bowser with integral generator and power washer unit was pinched from a building site off the A1307 at Withersfield between 4pm on August 5 and 8am on August 6.

Two witnesses told police that two other men were seen near the barriers of the site acting suspiciously around 9.45pm on Monday.

Police are keen to speak to these two men as they may have information which could help with enquiries.

The first man is described as white, of large build with a bald hair and he was wearing a white checked shirt.

The second man is also described as white, with a bald head, he was of larger build and wore a black top.

Call police on 101 to help.