A superior court judge reversed a Cambridge Rent Control Board decision last week in a move that could throw a wrench into part of the Massachusetts Institute of Technology's plans to develop a 27-acre site in Cambridgeport.

The judge ruled that the Board followed an "unlawful procedure" in giving MIT permits to either demolish or remove five rent-controlled buildings on the site of its University Park development.

In an April decision, the board ruled to let MIT demolish three rentcontrolled buildings on Blanche St. on the University Park development land, and to relocate two others.

Although the board initially denied the permits, it approved them in a last-minute switch when MIT offered to build an additional six rentcontrolled units in another location, according to the case memorandum issued by the Superior Court.

But last week, Justice Joseph S. Mitchell sent the case back to the rent control board for a second hearing. According to his written opinion, the board must admit previously unallowed evidence from opponents of the development.

Mitchell ruled that because the board let MIT present evidence that the project would increase the city's housing stock, it must also let members of the anti-development Simplex Steering Committee testify that University Park would push rents up, congest traffic and disrupt its neighbors in other ways.

In addition, he found that the board acted improperly in not telling the activists about its last-minute reversal.

Until the rent control board makes a fresh decision, development cannot proceed on that part of the site, which is slated to house a hotel complex.

MIT has 30 days to appeal the decision to the court. But Walter L. Milne, assistant to the president at MIT, yesterday said the university would not do so.

"There will be no appeal at all," he said. "We'll go back to the rent board; we will present the same things. I would expect them to act with reasonable consistency."

Members of the Simplex Steering Committee and the Cambridge Tenants' Union who appealed the board's April decision said the judge's ruling gave them a chance to present a case for the harmful effects of the development on future rent-controlled housing in the area.

"I think the court has reversed what was egregious on behalf of the Rent Control Board," said William S. Noble, a member of the Simplex Steering Committee and a resident of one of the buildings that MIT proposes to relocate.

Noble said that the removal permit ordinance imposes three criteria in judging applications to take apartments off of rent control of move them: the "aggravation" removal would cause to the rental housing stocks, the hardship to the tenants, and the benefit to the tenants.

"We feel the aggravation should be looked at," he said.

Noble said aggravation includes what he called a "cascade effect" that could let MIT remove additional rentcontrolled units in Cambridgeport.

"Our objection is that [MIT's plan] is not taking into account that there are 20 other units in the area which will be picked off in the same way," said William Cavelinni, a member of the Simplex Steering Committee.

"By coming in with little bites of the apple each time, MIT is trying to say, `We're not going to take the whole apple," Noble said.

The site on which the five buildings stand is slated to become the location of a hotel and parking lot, Milne said. He added that MIT's proposal to the rent control board would "take six units that aren't rent-controlled and we're going to construct another six units [under rent control.]"

But Cavelinni said this concession does not take into consideration the environmental effects on the existing Cambridgeport community, or the changes in the composition of that community.