MUNICH, WEST GERMANY, FEB. 7 -- The West German government probably will support modernizing battlefield nuclear arms in the future but wants to postpone public discussion of the issue for domestic political reasons, West German officials said today.

Senate Majority Leader Robert Byrd (D-W.Va.) and Sen. William Cohen (R-Me.) also predicted here that there would be an early resolution of a constitutional dispute between the Reagan administration and some U.S. Democratic senators that threatens to delay significantly ratification of the Intermediate-range Nuclear Forces (INF) treaty.

"This is just a little internal disagreement," Byrd said.

At the Wehrkunde conference, a high-level military affairs symposium here, West German Chancellor Helmut Kohl yesterday declined to commit his government to support deployment of updated versions of battlefield nuclear arms -- those with ranges of less than 300 miles.

Today, however, West German officials said the government was likely eventually to support modernization. Speaking on condition that they not be identified, they said the government was unwilling to commit itself publicly now because new arms deployment programs would be unpopular at a time of widespread enthusiasm over the INF treaty.

Defense Minister Manfred Woerner told the conference that "the decision taken at Montebello remains valid," referring to a 1983 North Atlantic Treaty Organization agreement in Montebello, Quebec, to modernize battlefield nuclear weapons. European-based nuclear arms must be modernized "whenever necessary," he said.

But Woerner declined to discuss specific modernization programs, saying it would be "counterproductive" at present.

Regarding the constitutional dispute over INF ratification, Byrd predicted that the administration would satisfy concerns raised by him and Senate Armed Services Committee Chairman Sam Nunn (D-Ga.). The two senators wrote a letter to Secretary of State George P. Shultz last week expressing their dismay over the administration's refusal to declare that testimony by administration officials about what the treaty means is binding.

Cohen also said he expected the dispute to be resolved "rather quickly," although he did not say how. The three senators attended the conference here.

The committee will hear no administration witnesses on the treaty until the issue is cleared up, so there will be at least a small delay in ratification as a result, Nunn said.