A builder has put up a hefty reward to anyone who can dob-in vandals responsible for trashing new-build homes in Beachlands last weekend.

Vandals hit three houses built by Plunkett Homes, one due to be moved into next week, causing tens of thousands dollars damage.

New wood floors, an airconditioning unit and kitchen bench will have to be replaced in one property on Dampier St after protective paint was strewn throughout the house.

Plasterboard ceilings were kicked off and a patio window was smashed at another home nearing completion.

It is believed the vandals struck on Friday night.