The Soviet Union has refused to resume negotiations -- recessed in December -- over rules for implementing provisions of the Strategic Arms Limitation Treaty, informed sources said yesterday.

A Defense Department source said the Soviet declared at a meeting in Geneva Wednesday that they would "not continue the discussions, since President Carter had indefinitely postponed" putting SALT II before the Senate for approval after the Soviet invasion of Afghanistan.

"They're tweaking our nose the way that we tweaked theirs," one government arms expert said yesterday.

A White House aide was more cautious. He noted that the Soviets had stated privately to U.S. negotiators even before the treaty was signed last June that they had no intention of being bound by its provisions while awaiting approval by the Senate.

To date, however, he said, the Soviet have lived up to the agreement.

"They may just be needling us," he said, "or this could be the beginning of the end. Nobody knows."

In December, U.S. and Soviet negotiators began talking about rules to govern conversion of Soviet bombers to tankers and a timetable for dismantling missile silos, actions that would be required after the treaty is approved and comes into force.

The Soviet Union, for example, would have to eliminate 104 of its ICBMs and bombers to get under the 2,400 strategic deliver systems limit that would go into effect six months after the treaty becomes operative.

The U.S.-Soviet talks on implementing SALT II took place last winter within the Standing Consultative Committee, a group established to oversee the first such treaty between the two countries.

When that group met Wednesday, the Soviet declined to take up anything but subjects relating to questions arising out of that SALT I agreement.

A number of arms control experts said yesterday that the real test of whether the Soviets intend to abide by SALT II will comne in the next few months. It is during that time, they said, that the Soviets are expected to begin their long-awaited tests of a new generation of land-based strategic systems.

If the Soviets launch a test missile with more than the 10 warheads permitted under SALT II, one official said, "that would be an irreversible violation."

Another possible area for violation would be if they build more than the roughly 2 1/2 Backfire bombers per month or the 30 per year agreed to at the Vienna summit.

Total encryption of missile data, a Defense Department official said, would also be a clear violation. The treaty requires the Soviet to sent without encryption radio signals from their test missiles giving data on weight and overall size, which are limited by provision of the treaty.

Although the Soviets refused to discuss SALT II matters, the consultative committee went on with discussion of SALT I questions, sources said, including a Soviet report on the dismantling of some antiballistic missile launchers and destriction of older submarines to make way for newer ones.

"These were actions we already knew about," a White House aides aide said yesterday.

U.S. and Soviet negotiators are also involved in meetings on the comprehensive test ban, a limit on chemical warfare and European force reductions.