VIENNA, Austria (AP) _ Twenty-five former Soviet citizens who emigrated to Israel will return to the Soviet Union in the next few days, and 30 to 40 more have asked to go back home, the Soviet consul said today.

Yuri Lysov gave the figures in reply to a question at a news conference organized by the Soviet Embassy for four of the returnees to explain their decision to leave the West.

Hairdresser Leah Shor, manual worker Semyon Kogan, doctor Margarita Kanayeva and her son Joseph each said they were unhappy abroad and thanked the Soviet government for allowing them to return.

Their often emotional statements were regularly punctuated by applause from Soviet journalists and other Soviet emigres who want to return home.

Samuel Zivs, who is chairman of the Soviet anti-Zionist committee, said the decision to allow unhappy emigres to return to the Soviet Union was part of ''a new approach to human questions'' in the Kremlin.

He said that the authorities in Moscow are also reviewing several thousand applications by Soviets who were turned down in their applications to emigrate.

Zivs announced last week in Moscow that the Soviet government has begun a major review of up to 10,000 emigration applications.

Zivs declined in response to a reporter's question to give figures for the number of former Soviet citizens who have returned home amid a blaze of Kremlin publicity which began last fall. Lysov said 13 former emigres left Vienna for Moscow in November.

On Dec. 29, 50 Soviet emigres who had lived in the United States for varying lengths of time returned together on an Aeroflot flight from New York, saying they missed other family members, their motherland, and found life in the United States difficult to adjust to.