Agriculture Secretary John R. Block gave a clear signal yesterday that the administration would sell surplus dairy products on the world market.

Despite misgivings that "any dairy products that we do sell abroad . . . are subsidized," Block said on the NBC's "Meet the Press," "it is very likely that we will find some way to sell these commodities." Last week, he announced plans to donate some of the nation's surplus dairy stocks to poor countries.

The dairy price support system costs taxpayers about $12 billion a year. and selling the dairy products in the world market, where prices are lower than in the United States, would amount to a U.S. subsidy to the foreign purchaser.

Block acknowledged that such subsidies are "an approach I'm very much opposed to," but said that "in order to justify that, you're going to have to do it as a one-shot affair or a certain small amount, maybe not something that you would institutionalize."

Dairy officials from New Zealand, a major milk-products exporter, have expressed concern that a U.S. sale of surplus dairy products would hurt that country's export earnings. Block and Vice President Bush have given assurances that the U.S. would not dump surpluses on world markets.