Massachusetts' four-year-old gun control law has reduced the number of gun-related assaults and homicides but may also be responsible for a substantial increase in assaults with other deadly weapons, according to a report released yesterday.

The study conducted by Northeastern University says that because of Massachusetts' Bartley-Fox gun law - mandating a one-year prison term for unlicensed handgun possession - "some offenders may actually be more likely to become involved in assaults now that they (and perhaps their adversaries) are no longer carrying a gun."

The study found that gun assaults in the state had declined more than 15 percent since the law was adopted in April 1975. But, conversely, assaults with other deadly weapons increased 24 percent.

"Indeed, it would appear that when potential offenders find themselves in assaultive circumstances without their guns, they are more likely to get involved in a fight," the report concluded.

The report, financed by the Law Enforcement Assistance Agency, is expected to provide a new arsenal of statistics for both advocates of gun control on one side, and the powerful gun lobby on the other. The report could also be significant in the upcoming congressional battle over gun control since it focuses on the gun law of the home state of gun control's leading proponent in the Senate, Edward M. Kennedy.

Kennedy will be introducing his own legislation for federal guns control, patterned after the Bartley-Fox law, within the next few weeks, according to an aide.

"The Massachusetts law is having an impact on handgun crime," said Charles Orasin, executive vice president of Handgun Control Inc. "Even if there is substitution of a knife, a club or a fist, the number of fatalities is less. The kind of law Massachusetts now has we are weeking on a national level."

The National Rifle Association vowed to fight any legislation like Kennedy's which would "penalize people for the mere possession of firearms." John Adkins of NRA's legislative lobbying arm yesterday called the finding of increases in nongun crimes "not surprising."