In his final speech to the United Nations, President Reagan will call for an international conference to seek a worldwide ban on deadly chemical weapons, White House officials said Saturday.

The president, spending the weekend at Camp David, Md., planned to fly to New York Monday for a two-day whirlwind visit highlighted by his seventh and last speech to the world organization.In a prelude radio address Saturday, Reagan said: "This year, as we survey the scene one last time, we can see that our strength has indeed proven to be the engine of peace and hope in the world."

White House officials said that one of the new initiatives in Reagan's speech to the U.N. General Assembly would be to propose an international conclave to recommend ways to tighten curbs on chemical weapons. Reagan's move, the officials said, reflects growing concern over the use of poison gases in regional conflicts.

Both Iraq and Iran used gas and other chemical weapons in their eight-year Persian Gulf war.

Administration officials said that Reagan will not single out any nation but will express concern that the enforcement of sanctions against poison gas have weakened since they were largely observed in World War II. Such weapons were widely used in World War I.