Tougher penalties for defacing buildings and for wearing Ku Klux Klan-style masks -- measures aimed at blocking possible racial and religious violence -- were proposed at yesterday's meeting of the Prince George's County Council.

The anti-hate violence measures were introduced by Vice Chairman Floyd Wilson in the wake of the violence in downtown Washington following a Klan and counter-Klan rally on Nov. 27.

"This is taken from the D.C. experience," said Wilson, a three-term member who was elected as the council's first black member eight years ago. "This is an ounce of prevention before something occurs. My concern is that whenever the Klan meets, it is a menace to the health and welfare of the people in that community."

One bill sets a penalty of 180 days in jail and/or a $1,000 fine for defacing a building without the consent of the owner. Wilson said his bill is modeled after legislation drafted by D.C. City Council member David Clarke, and is intended to go further than existing state law. It would make the punishment for defacing buildings with grafitti, particularly with markings motivated by racial or religious bias, almost as severe as for physical destruction of property.

The second bill makes it a misdemeanor to wear a mask with the intention of depriving a person of his equal rights or intimidating him. It would not, according to a county legal adviser, prohibit the wearing of masks solely for demonstrations. The county already has an ordinance prohibiting cross burnings.

The council yesterday also approved $1.3 million in new one-year labor contracts with physicians, nurses and support workers at the county's three hospitals.

Unionized physicians who are in training at the hospitals voted 54 to 14 in mid-November to reject the county's final proposal and to prepare for a strike, but they resolved their differences with the county in another meeting later that month, according to a spokesman.

The approximately 600 staff nurses, according to their representative, had also declared themselves at an impasse earlier this fall, but approved a contract in late October and signed it Monday.

The contracts approved yesterday ended lengthy negotiations between the county and the unions, which were delayed while former county executive Lawrence J. Hogan tried unsuccessfully to lease the hospitals to a private firm.

The agreements with the resident doctors, staff nurses, and the International Brotherhood of Firemen and Oilers (which includes clerical, dietary and housekeeping employes, as well as licensed practical nurses) generally provided 5 percent salary increases and a variety of benefits. The county agreed, for example, to provide shower facilities for resident doctors, who work 36-hour shifts, and formalized job protections for nurses who work 12-hour weekend shifts.

Also yesterday, council members Sue V. Mills and JoAnn Bell reopened the lengthy and bitter controversy over the location of Metrorail's Green Line by introducing a measure to return its alignment to Branch Avenue.

In 1978, the council voted to change the alignment from Branch Avenue to a stop near Rosecroft raceway, a decision that the Metro Board reaffirmed last month.The proposal will be debated at a meeting on Jan. 17.