Construction has begun on a controversial hotel development in Amherst just as the town mounts a new effort to stop the project.

Iskalo Development on Thursday received a building permit for its proposed Hyatt Place Hotel, and backhoes have already begun clearing trees for the site along I-290.

Town Supervisor Barry A. Weinstein, seen by some as previously supportive of the hotel, is now planning a legal challenge, which he will ask the Town Board to approve Monday.

The effort could derail the project before serious work ramps up.

“It would send it back to square one,” Weinstein said Friday of his effort.

If successful, the legal challenge would invalidate a previous Zoning Board ruling that wiped out a two-story height restriction on the property.

The zoning board’s overturning of the 1969 height restriction allowed the six-story project to go forward and created an uproar among neighbors living behind the hotel site.

But Weinstein now says the Zoning Board had no right to overrule the building commissioner, who wanted to enforce the height restriction.

“We think it will be thrown out,” he said of the Zoning Board’s decision.

The board never produced a written explanation for easing the height restriction, he said.

The challenge – actually an appeal to a previous State Supreme Court ruling upholding the Zoning Board’s actions – could have ramifications for other projects beyond the Hyatt proposal.

“The feeling is other lawyers would line up to say their clients’ zoning restrictions are no longer valid,” Weinstein said.

The threat of the $15 million project being stopped midway through construction does not appear to worry the developers. “I wouldn’t be too concerned about this because everything I’ve been informed, the Zoning Board has the absolute authority to overrule the building commissioner,” said David Chiazza, executive vice president of Iskalo.

Development of the Hyatt hotel – and a nearby hotel built by Carl P. Paladino – has become a central theme in the escalating race for Amherst supervisor.

Outraged residents of Livingston Parkway – whose properties abut the hotel site – have blamed Weinstein for the project’s approval and vowed to bankroll the campaign of his opponent, Council Member Mark A. Manna.

They cite the Paladino hotel and the Hyatt plan as proof the town is too developer-friendly at the expense of average residents who live near the properties.

But Weinstein on Friday made the strongest defense of his actions to date, pointing out that he voted against tax breaks for the site and opposes a six-story structure in that location.

“No one on the Town Board’s been more anti-development than me,” Weinstein said. “I’ve voted against more rezoning and more taxpayer subsidies than anyone else. What else to I need to do to prove I’m against it?”

He noted that the project never came to a vote before the Town Board and sought to distance himself from the Zoning Board, whose members he has appointed and whose ruling he is now challenging.

Residents “are making it sound like I have extraordinary power” to stop the project, Weinstein said. “Clearly I do not.”

He called his and Manna’s approach to development in the town “not far apart” but said he is pursuing the issue through different channels.

“He comes at it as a community organizer. I come at it as a lawyer,” Weinstein said. “I’m not organizing residents. I’m moving something through the legal process and channels to impact the project going forward.”

Manna, though, called Weinstein’s stance a “180” from his original position and said “it’s sad that it took so long for him to realize he was wrong.”

The hotel property was zoned for business, but Iskalo received a slew of variances from the Zoning Board – changes the residents contend will devalue their properties and even put the safety of their children at risk.

New construction at the site caught some by surprise, especially since three lawsuits against the project have been filed by residents and are weaving their way through the courts.

A possible legal challenge by the town – which has to this point let the project roll forward – also surprised them.

“He’s been reading the stuff I’ve been putting out, perhaps,” resident Michele Marconi said of Weinstein. “I’ve been saying the same things.”

Iskalo got the green light for the building permit more than a month ago but had not picked it up until Tuesday, when company officials paid $88,000 for the document.

“We are prepared to go forward,” Chiazza said. “At the end of the day, our business involves taking risks of all kinds.”