MOSCOW, JAN. 23 -- Naum Meiman, a veteran human rights activist who has been trying to emigrate from the Soviet Union for 12 years, said today that a high-ranking Soviet official has confirmed that he will soon be allowed to leave.

Meiman, 76, said the Soviet ambassador to France yesterday telephoned former French health minister Simone Veil, an active supporter of his case, to inform her directly that Meiman's visa had been approved. Meiman said Veil called him from Paris last night.

Meiman, a mathematician who worked on the Soviet nuclear program more than 30 years ago, was one of the people who had access to state secrets whose cases are under review by a special commission. The commission has approved several visas for "refuseniks" who had been repeatedly denied visas because of "secret work" they had done in the past.

Several Soviet scientists, including physicist Andrei Sakharov, have stated publicly that the work done by Meiman at the Institute for Physical Problems in the 1950s is no longer classified and is out of date.

Meiman's case has received widespread publicity and the U.S. Senate recently passed a unanimous resolution urging Moscow to let him emigrate. According to Meiman, a recent U.S. congressional delegation here was told that good news would be announced soon.

"They have a very indirect way of telling you their decision," said Meiman. "But it is difficult to imagine that the Soviet ambassador would call such a famous person as Madame Veil and not tell things as they are."

Meiman is one of the last of the veteran refuseniks still in Moscow, following the departure of Alexander Lerner, Vladimir Slepak, Josef Begun, Ida Nudel and others who received visas in recent months after more than a decade of waiting.

Meiman, a member of the original Moscow group monitoring compliance with the 1975 Helsinki accords, spent most of his time and energy in recent years getting an exit visa for his wife, Inna Kitrosskaya Meiman, who suffered from cancer. After intercession by Secretary of State George P. Shultz among others, she finally got permission to leave for medical treatment last year, but died in a Washington, D.C., hospital.

Meiman, whose daughter lives in Colorado, was denied permission to go to the United States for his wife's funeral.

Since his wife's death, Meiman has waited, watching as his contemporaries left one by one. In all, more than 8,000 Soviet Jews emigrated last year, an eightfold increase over 1986.

Meiman, whose mood had been growing pessimistic of late, was clearly elated by the news from Paris.

"But," he said, "I cannot call it pure joy because it came too late. If it had come on time, I believe Inna would be alive today."