Expensive construction machinery is being set alight by arsonists, causing expensive delays to the Christchurch rebuild.
A $120,000 digger was destroyed by fire early on Tuesday in an empty section at north New Brighton.
Earlier this month a $750,000 drilling rig working in the central city red zone was targeted by arson, burning out the cab.
It follows a pattern of arsons in abandoned eastern suburbs red-zoned properties over the past several months.
The arsons of machinery have caused delays in some rebuilding projects to be delayed by more than four weeks.
Paul Flanaghan of Paul Flanaghan Contracting was frustrated by the arson to his digger.
"We are flat out at the moment - we don't need this. I had a crew down doing no work while we tried to find a replacement. We have had to hire a digger at $300 a day - and now I have just been told there is nothing around second-hand wise that we can buy to replace it," he said.
Smith Cranes and Construction managing director Tim Smith said their drilling rig had been bought in from the US to help with the rebuild. It was set on fire two days before its first job, causing more than $50,000 worth of damage.
Mr Smith said major projects in central city red-zone were delayed because the machinery was difficult to replace.
"There are very few of these machine around and we have only just managed to replace it, putting our project behind by more than four weeks," he said.
Six cars have also been targeted by arsonists over the past fortnight. Fire investigators were unsure if they are linked but are keeping a watch on the situation.