The owners of United Press International have agreed to consider selling more than 50 percent of the financially troubled news service, a company official said yesterday.

Some UPI employes had said the concession would be necessary to induce a major investor to save the struggling company from possible bankruptcy.

Media News Corp., UPI's privately held parent company, had previously agreed to sell only 30 percent of the company's stock, refusing to yield majority control.

But a proposal to buy a controlling interest "would be considered," said Luis Nogales, executive vice president and general manager, adding that there would be "advantages to staying with the current owners."

Selling control of the company "would delay the strengthening of UPI," Nogales said. The current owners have "a strategy in place" to diversify the company, raise more capital and market more aggressively so that the company "is not always barely operating at cost."

Executives of the Wire Service Guild, the union representing most of UPI's editorial employes, yesterday issued a statement to its members saying that management "is considering all options open to the company in its efforts to survive."

After two days of discussions with UPI's owners, the union said management had indicated that it is conducting "talks with several potential investors that could bring additional revenue to UPI, following ratification" of a proposed agreement on contract concessions.

The union yesterday mailed about 900 ballots to employes who will vote on the package of proposed contract concessions, which includes a net pay cut of 13.8 percent over 13 months. The ballots will be counted Sept. 17.

The union has recommended that its members approve the agreement as a way to prevent the demise of the wire service.

Nogales said the company will survive until the vote, and will generate a profit if the package is approved.