''We saw a need for them to have a base, so we approached ITM and Certified Builders with the idea of building an office,'' he said.
The build was to have happened two months ago, but was held up by Covid.
Other firms came to the party, with, for example, Bay Windows donating windows and First For Electrical donating and installing all electrical fittings.
Anything not donated by suppliers had been provided by Bay of Islands ITM, owner Stephen Gray said.
''There are plenty of good causes out there, but this is one where we could make a genuine difference," he said.
Under normal circumstances he estimated the office would have cost around $25,000 to build.
It is due to be delivered to the charity's property today, also without charge.
Bay of Islands Animal Rescue is an independent group established in 2016 by Kawakawa woman Summer Johnson. Since then it has rescued, fostered and rehomed thousands of animals, mostly dogs, but also horses, cats, pigs, and anything else that needs help.
In August alone the group rescued 131 dogs, 76 of which went to Auckland for rehoming, while 55 are in foster homes in Northland.