A new proposal has been made by the Soviet side at the long deadlocked East-West troop reduction talks in Vienna and includes "some positive elements," a White House official said yesterday, but the main stumbling block appears not to have been removed.

State Department officials said that, at first glance, "the most interesting and positive" aspect of the draft agreement put forward last week is that the Soviet-led Warsaw Pact countries appear more receptive than ever to such things as permanent observation posts on each side to verify compliance with troop withdrawals.

The Vienna talks, begun in 1973, have become one of the longest running and least productive arms control exchanges between the the seven countries of the Warsaw Pact and 12 participating countries of NATO.

The idea behind the mutual and balanced force reduction (MBFR) talks is to reduce the fear of conventional war in central Europe by a gradual reduction in troops and tanks on both sides to equal levels below those currently deployed.

But the talks have been hung up for years because the two sides do not agree on how many troops are there now and thus cannot agree on how many troops to withdraw to achieve equality.

Both sides want to reach a common ceiling of 700,000 ground troops and 200,000 air force personnel. But the West claims the Warsaw Pact has 960,000 ground troops in comparison to 800,000 for NATO and so must cut its forces by 260,000. The Warsaw Pact insists that the ground forces are roughly equal at 800,000 and therefore it only must reduce by 100,000 troops.

The new Warsaw Pact proposal, which was made June 24 and is being studied by the Reagan administration and the NATO allies, does not appear to offer any new solution to this problem.

But it calls for an "immediate implementation, as a first step, of a reduction of a certain part of the troops and arms of the U.S.S.R. and U.S." American officials speculated said this could be an effort to start the reduction process and might help improve the atmosphere and eventually resolve the deadlock over levels of troop strength.

But these officials all cautioned that the Warsaw Pact language was very vague and the difference over troop estimates remained a central one. "Our preliminary reaction," a White House official said, "is that the eastern proposal contains some positive new elements, while still inadequate in other respects."

The NATO nations offered a new proposal, emphazing the need for verifiable reductions, last July. The new Warsaw Pact proposal, which is in the form of an agreement rather than a formal treaty, envisions the total reductions over a three-year period with "sufficiently effective verification" procedures.

Among the proposed measures, according to a Soviet Tass news agency account of the proposal, are "invitation on a voluntary basis of observers" to witness the withdrawals, establishment on each side "after the carrying out of all reductions of three or four permanent posts for observation," the "possibility of verification on the spot with the observance of certain demands," and the "commitment of each side not to put up obstacles to the national technical means" of each side.

The last reference is to various electronic and photographic techniques used to monitor each side's forces.