MOSCOW (AP) _ A maritime official said Tuesday that 1,230 people were aboard the Soviet cruise ship that collided with a freighter in the Black Sea and sank. Officials said lives were lost, but did not give a casualty figure.

The 61-year-old Admiral Nakhimov sank some nine miles out to sea around midnight Sunday about an hour after leaving port at Novorossiysk, Igor M. Averin, a spokesman at the Ministry of the Merchant Marine, told The Associated Press by telephone.

The official news agency Tass said Monday without further detail that there was ''loss of life'' in the collision and that help was being given to the injured.

Averin said he did not yet know how many people were killed or injured. There were 884 passengers and 346 crew members aboard the Admiral Nakhimov when it sank, Averin said. All were Soviets, he added.

He said he did not know how many crew members were aboard the Soviet freighter.

Search and rescue operations continued Monday night, about 20 hours after the liner went down, according to officials in the Black Sea ports of Odessa and Novorossiysk.

Soviet media carried only a brief statement on the accident from the Communist Party Central Committee and Soviet government. It was the second sinking of a Soviet passenger liner in seven months.

The official announcement, distributed by the Tass news agency, said only that the 17,053-ton Admiral Nakhimov ''collided with a cargo ship not far from Novorossiysk'' and sank ''on the night of Aug. 31.''

''Rescue measures have been taken,'' the official news agency said. ''The necessary assistance is rendered to those affected. There has been loss of life.''

Lloyd's Registry of Ships, published in London, says the ship had berths for 870 passengers. A Soviet citizen who sailed on it in 1971 said many other fourth-class passengers customarily slept on the uppermost of its four decks.

The Admiral Nakhimov, which Lloyd's says is 575 feet long, was built in Germany in 1925 as a steam-powered vessel and later refitted with diesel engines.

An official of the Black Sea fleet in Novorossisyk, reached by telephone from Moscow, said that whether ship went down late Sunday night or very early Monday still was not known. That indicated it sank quickly.

In Turkey, across the Black Sea, none of the major radio stations monitoring maritime frequencies along the coast reported hearing an SOS from the Admiral Nakhimov.

All the monitors said they could pick up Novorossiysk, about 60 miles southeast of the Crimean Peninsula.

Tass said a government commission was appointed to investigate the collision and sinking, headed by First Deputy Premier Geidar A. Aliev, a member of the party's ruling Politburo. Choice of Aliev as commmission chairman indicated the seriousness of the accident.

He also led the state commission that investigated the crash of a Volga river cruise ship in June 1983, in which unconfirmed reports said more than 200 people perished.

The Admiral Nakhimov, originally named the Berlin, was taken and renamed by the Soviets after World War II. Nazi Germany is believed to have used it as a hospital ship.

Adm. Pavel Stepanovich Nakhimov was a defender of Sevastopol during the Crimean War of 1854-55.

The vessel named for him became the flagship of the Black Sea cruise fleet in the 1950s. Most recently, it is said to have been used for the six-day run between the Soviet Black Sea ports of Odessa and Batumi.

On Feb. 16, the Soviet cruise ship Mikhail Lermontov struck a reef off the coast of New Zealand and sank. Reports at the time said 792 passengers and crew were rescued and the only death was of a crew member.

Soviet officials blamed the accident on a New Zealander acting as pilot, but the government newspaper Izvestia reported last Saturday that the Mikhail Lermontov's captain was fired.

Izvestia said the senior navigator was convicted on charges it did not specify, given a four-year suspended prison sentence and fined the equivalent of $30,000.