A detailed plan for settling tens of thousands of Jews in the occupied West Bank of the Jordan River was contained in a published report today attributed to Israeli settlement chief Ariel Sharon.

The daily newspaper Maariv said the purpose of Sharon's plan would be to prevent "the spread of Arab population, which might pose a security problem." There was no official confirmation of the report, but it agrees with several of Sharon's previous statements.

Leaders of the ultra-nationalist Gush Emunim movement said, meanwhile, that they plan to establish 12 new Jewish settlements in occupied Arab areas by the end of this year with or without Israeli government aid.

Some of the 12 settlements listed by Gush Emunim have already been approved in principle by the government, but little official effort has been made to get them going.

Despite the threat to go ahead without government aid, the Gush Emunim said it would not defy a government order to desist. But so far the government of Prime Minister Manahem Begin has shown no sign of giving such an order.

Any moves by Israel to establish more settlements on lands it captured in the 1967 Arab-Israeli war would be sure to draw sharp criticism from Washington. The Carter administration has already called such settlements "an obstacle to peace" in the Middle East.

The Sharon blueprint, as reported by Maariv along with a map, would bind the West Bank to Israel by constructing more highways cutting across the 1967 frontiers and urban centers administratively linked to Jewish communities inside Israel.

The newspaper said the settlements would not be built inside Arab population centers, but would be interspersed among Arab villages.

Foreign Minister Moshe Dayan told Parliament today that he would take "a proposal for the text of a peace treaty" to Washington later this month to begin negotiations with the Arabs. Dayan did not disclose what Israel would offer.

Dayan and Arab foreign ministers will be in the United States this month for the opening of the U.N. General Assembly session. Sources said Dayan would have full powers "to present ideas and to accept ideas" from the Arabs.

Meanwhile, the Israeli parliament passed two tough resolutions branding the Palestine Liberation Organization an "organization of murderers" and excluding it from Middle East peace talks.

The Resolutions followed a statement by Begin last week that if the Arabs insist on seating the PLO, Israel will reject reconvening the Geneva peace conference.

At the end of a six-hour foreign-policy debate, the Parliament adopted a resolution sponsored by an opposition party, the centrist Democratic Movement for Change, calling the PLO a band of killers and saying that the "PLO is not a partner for Israel for negotiaions for peace in the Middle East."