JERUSALEM, NOV. 16 -- The right-wing government of Prime Minister Yitzhak Shamir was bolstered today when a small religious party signed an agreement to join the parliamentary coalition after winning support from Shamir for new religious laws likely to anger many secular Israelis and cause some economic disruption.

The four added votes from the religious party, Agudat Israel, gave Shamir a secure parliamentary majority -- 66 in the 120-member Knesset -- for the first time since the government was formed in June and could allow it to stay in office for up to two more years.

The alliance, which pairs Shamir's Likud Party with four religious parties as well as ultra-nationalist factions, should be able to operate with more confidence, analysts said, no longer so vulnerable to the frequent threats of small factions to quit and bring down the government.

The price for the government's added stability was its agreement to support passage of four pieces of legislation sought by Agudat Israel, which would ban the sale of pork in most of Israel, tighten restrictions on abortion, halt public transportation in most of the country on the Jewish Sabbath and prohibit "lewd advertisements."

Government officials said the new laws could be passed as early as next week. Meanwhile, three of the four parliament deputies from Agudat Israel will be given deputy ministers' posts, while the fourth will be put in charge of the parliament's powerful Finance Committee.

Today, the party's leaders made clear that their entrance into the coalition is contingent on the passage of the new legislation, which is expected to be controversial with secular Israelis.

Under the pork law, Israeli producers and retailers of the meat will be put out of business and will have to be compensated by the government, while the ban on Saturday public transportation could inconvenience thousands of workers who commute by bus.

Both Jewish and Moslem religious law forbid the consumption of pork. But a parliamentary committee that held hearings on the proposed new law last summer heard protests from collective farms that process the food as well as 1,000 Israeli restaurateurs who serve it.

Christian leaders in Jerusalem protested the legislation, saying it infringed on their rights by banning pork sales in Jerusalem, where about 20,000 Christians live. According to the draft law, some pork sales will be allowed in other Christian communities, such as Nazareth.

The new legislation on abortion calls for stricter enforcement of Israel's tough existing laws, which oblige women to obtain approval from a panel of doctors before terminating a pregnancy.

Party officials said today that the legislation on advertising had not yet been clarified so as to define what would be proscribed as "lewd." In recent years, ultra-Orthodox militants have attacked commercial advertisements for products such as chocolate bars containing mildly suggestive language, in some cases setting fire to bus stops where the ads were posted.

Unless there is a crisis in the coalition, Shamir will be able to remain in office until the fall of 1992, when new elections are mandated.