Coromandel MP Scott Simpson says thieves are targeting the contractors repairing land devastated by flash flooding earlier in June.
Farmers in the area say a metre of rain fell in just six hours leaving hundreds of hectares of land unusable.
Mr Simpson, who has visited the area, said he had spoken with contractors who were targeted by thieves during clean-up work.
He said a number of the contractors had their private vehicles broken into and petrol was siphoned, personal possessions stolen and car batteries taken.
"It takes a particularly low form of life to do that when the community is under stress."
Mr Simpson said he was shocked at the devastation caused by the storm.