Toyota Motor Co. hinted today that it is having second thoughts on its proposal for a joint venture with Ford Motor Co. to produce small cars in the United States.

"We think there may be some difficulties in setting up a new company in the form of a joint venture" with a 50-50 equity, a Toyota spokesman quoted a Toyota official as saying.

The companies have been negotiating the creation of an equally owned venture to produce 2,000-cc-class passenger cars at idle Ford plants.

In Dearborn, Mich., Ford Motor Co. said that discussions between its management team and Toyota are continuing in Japan and that when the latest round of talks is concluded next week the company expects "further progress towards a go or no-go decision."

The Toyota spokesman also said, "We haven't given up" hope for an agreement by the end of June, the previously set deadline.

The officials were responding to reports that Toyota is considering abandoning the joint-venture idea in favor of a licensing arrangement whereby Ford would produce Toyota-designed cars under license. Under that arrangement, Ford would see under its own brand name but would produce the cars using parts and designs supplied by Toyota.

The reports said Toyota was disenchanted with the joint-venture approach because of difficulties in deciding which company would have the majority stake in it. The reports also cited concerns about U.S. antitrust laws and the effect of Toyota of an Arab boycott against Ford.

A statement from Ford Vice President H. A. Poling, head of North American operations, said the reports about Toyota's balking on the joint-venture proposal were highly premature and speculative.