Former defense minister Ezer Weizman has announced that he is setting up a new political party to challenge both Prime Minister Menachem Begin's ruling Likud bloc and the opposition Labor Party in next year's national elections.

Weizman, 56, said Friday he would like to see another defector from the Begin Cabinet, former foreign minister Moshe Dayan, head the new party.

A British-trained combat pilot considered one of the architects of Israel's modern Air Force, Weizman said he would settle for the defense portfolio in any new government that might be formed by his party.

National elections are scheduled for next November, but there is growing speculation that Begin might resign and move them up to May or June. Begin's coalition narrowly survived a crucial no-confidence vote in parliament Wednesday.

Both Weizman and Dayan voted with the opposition against the government.Weizman is facing expulsion from the Herut Party, the core of the Likud bloc, for his action.

Weizman's move had been expected since he quit the Begin Cabinet in May in a row over defense cuts and the government's policy on the Arab-Israeli conflict. Dayan resigned from the government last October, citing disagreement with Begin's Middle East policy.

Weizman said a government to be formed by his party would seek to bolster peace with Egypt and would not be averse to the emergence of a "Palestinian entity" in the West Bank and Gaza after three to five years of autonomy as outlined in the Camp David accords.