Copper thefts tended to be cyclical but had eased off recently in the region, Mr Robinson said.
Bay of Islands Hospital operations manager Shirley August said the theft was "a great disappointment".
"Now we have to divert money towards something that did not need replacing, and will not be able to use that money for the health of our community," she said.
Mr Robinson urged anyone with information about the theft to call Kawakawa Police on 09 404 3150 or Crimestoppers on 0800 555 111.
Meanwhile, police are still looking for the people behind a brazen theft of spouting and downpipes from Kaitaia Primary School during the summer.
The copper was stolen in broad daylight on the morning of January 5. Despite high-resolution CCTV images showing a man on the roof passing guttering to a woman on the ground below, no one has been able to identify the offenders.
Anyone with information about the Kaitaia theft, or who can identify the people, should call Houhora police on 09 409 8822 or Kaitaia police on 09 408 6500.