The condition of D.C. police officer Pauline V. Howard, who was shot and critically wounded Monday night by an unknown assailant in Northeast D.C., has improved and she is expected to live, Washington Hospital Center officials said yesterday.

The shooting of Howard and the slaying of another officer, Donald G. Luning, last week prompted a police union official yesterday to demand that the department issue bulletproof vests.

Such vests, said Gary Hankins, head of the Fraternal Order of Police labor committee, could have stopped bullets in both these police shootings.

A hospital spokesman said yesterday that Howard's condition has improved from critical to serious but stable and that she is now conscious and talking.

Howard, 27, was shot once in the abdomen with a .22-caliber pistol after a robbery suspect she had approached at 19th Street and Benning Road NE suddenly pulled a gun and opened fire.

Both shootings involved officers seemingly on routine duties. Luning, an 11-year police veteran, was shot in the chest with his own .38-caliber service revolver and killed last Tuesday while trying to question a 19-year-old about an auto theft.

"If this city wants its police officers to protect them, they've got to provide the officer with some kind of protection against physical abuse," Hankins said yesterday.

Hankins said that the police department's planning and development division has been researching bulletproof vests for the past two years. "We want them to stop studying and begin issuing," he said.

Senior D.C. police officials were out of town at a management seminar yesterday, and a departmental spokesman said he could not comment on the status of vests.

Hankins cited an FBI report that said that of the 49 law enforcement officers shot and killed last year all but four would have survived had they been wearing bulletproof vests.

Some jurisdictions issue protective vests to officers as part of their uniforms, Hankins said. The average cost for a vest is about $150, he said.

Hankins also said yesterday that he plans to ask the U.S. Attorney's Office "to toughen up" on the prosecution of cases involving assault against a police officer. "In 1980, 376 D.C. police officers were assaulted with a dangerous weapon; something must be done to discourage this type of abuse," he said.

Joesph diGenova, principal assistant U.S. Attorney for the District of Columbia, said yesterday that Hankins had asked for a meeting. "I would only say that we are as concerned as they are about their safety and will continue to be," diGenova said.