A battle between the state auditor and the attorney general has erupted over the MBTA zoning law and whether or not the multi-family directive amounts to an unfunded mandate.

Wrentham, Middleboro, and Methuen all sent letters to Auditor Diana DiZoglio’s office last year, requesting the Division of Local Mandates in her office weigh in on the MBTA Communities Act, a zoning plan that has already been approved in more than 115 cities and towns across Greater Boston.

DiZoglio’s office responded in a letter to the three municipalities last Friday that the act “does not provide a funding mechanism for compliance with its provisions” and that the state Legislature failed to appropriate funds when the law passed in 2021.

Towns and cities can now seek a Superior Court order exempting them from compliance until the state provides funding, the auditor said.

That led to a response from Attorney General Andrea Campbell, who said Monday, “The Auditor’s claim that the MBTA Communities Law is an unfunded mandate is wrong.”

The AG’s statement continued, “more importantly, this letter has no effect whatsoever on implementation of the Law.”

In an interview on Wednesday, DiZoglio told WGBH that she agreed with the AG: Her office’s determination doesn’t take away from how the state Supreme Judicial Court ruled in January that the law is constitutional and enforceable. That ruling came in the AG’s fight with Milton, the first town to vote against compliance.

“The attorneys in the Division of Local Mandates did their job,” the state auditor said, “they responded. They said ‘Yes, this does need to have a funding mechanism associated with it.’ Communities have the right to petition court for any reason if they feel like they’re not being funded.”

DiZoglio highlighted how the state housing office has set up a grant program to help the 177 cities and towns comply with the legislation that requires them to have at least one zoning district of reasonable size where multifamily housing is permitted as of right.

But the program doesn’t fulfill the Local Mandate Law because it is “discretionary funding,” DiZoglio said, meaning communities need to apply and receive the grants that help cover consultant costs during planning and design.

The Division of Local Mandates will also be studying the fiscal impacts of the zoning on the communities with the required zoning.

Middleboro Town Manager James McGrail said Monday that his Plymouth County town, of roughly 25,000 people, has estimated the zoning could lead to a “perpetual” annual budget cost of $21 million or a “one-time capital cost” of $617 million.

The Middleboro Select Board met in an executive session Wednesday to discuss their next steps.

Cities and towns must comply with the law by the middle of July.

Wrentham, a Norfolk County town with a population of 11,000, has fought the mandate for over a year. In December, residents voted 542-53 against two proposed zoning districts that would have met compliance.

The Select Board has argued that zoning at least 50 acres near downtown for multi-family housing, with 15 units per acre and a capacity of 750 units, could lead to a 13% population increase.

“Nothing has changed,” Select Board Vice Chairman Chris Gallo said Tuesday night. “As I’ve said before, asking us to vote this in without knowing the price tag is ridiculously irresponsible. Anyone who wanted us to do that I think should be ashamed of themselves.”