Senate Finance Committee Chairman Robert Dole (R-Kans) said yesterday that any attempts by the Reagan administration to dilute the Office of the U.S. Trade Representative will be thwarted by his committee.

Dole, during an address before local business leaders at The Washington Post, also said he didn't think the government "should impose quotas on sales of Japanese cars here, as the Ford Motor Co. and the United Auto Workers union have requested. He also said the government shouldn't "somehow interfere with what the International Trade Commission did" in rejecting Ford's and the UAW's pleas for import relief.

Legislation to aid the auto industry as well as measures to alter the status of the trade representative would have to go through Dole's committee. Dole said the trade representative office wouldn't be abolished or made a part of the Commerce Department because the committee's members feel international trade should be strengthened, not weakened.

Some members of the Reagan team have said they want to see the trade representative's office abolished or placed below its current Cabinet-level rank. Commerce Secretary-designate Malcolm Baldrige on Tuesday said he felt the government's trade functions were too diffused throughout different departments.

But Dole said following the address that he and the committee's ranking minority member, Sen. Russell B. Long (D-La.), opposed diluting the trade representative's powers and that there was "almost solid Finance Committee feeling against it."

"I don't think those of us in the Senate Finance Committee want to deemphasize that role of the special trade representative," Dole said. "So I feel very strongly" that dilution of that office "won't be accomplished."

Dole also said that efforts to create a new department of trade as proposed by Sen. William V. Roth Jr. (R-Del.) probably wouldn't have much luck, either.

"I just doubt there'll be any additional departments created under the Reagan administration," Dole said. He said there will be "more emphasis on trade, but it will have to be worked out within the present structure."

Dole had other doubts. "I doubt, myself, whether we should impose quotas [on Japanese cars] or somehow interfere with what the International Trade Commission did. . . . I would hope we don't get into that business."

Dole said other alternatives to help the domestic automakers should be available, but "they're all very costly."