Earlier reports cited China's Foreign Ministry as saying that the Kapitan Uskov dry cargo ship - declared missing in Pacific waters on Thursday when it was due to arrive in Hong Kong with over 4,500 metric tons of rolled metal - had been spotted by Chinese rescuers.
"China's Foreign Ministry has not confirmed reports that the Kapitan Uskov has been spotted," said Alexander Isayev, press attache of the Russian Embassy in the Chinese capital.
The Cambodian-registered vessel, which left Russia's Far East port of Nakhodka on January 15, last had radio contact on January 20.
The sea rescue center in Russia's Far East port city of Vladivostok also rejected the reports.
"The latest reports from China said rescuers are continuing the search for the Kapitan Uskov cargo ship," center spokesman Veniamin Ivanychev said.
Russian vessels and Japanese coastguard boats and aircraft suspended their search efforts on Monday. Ships passing the East China Sea, which have been informed of the disappearance, are monitoring the sea surface.
Shipping experts have offered two main theories on the disappearance, saying the heavy cargo could have shifted causing the vessel to list and then sink, or that the ship could have been attacked by pirates wanting the rolled metal worth millions of dollars.
"Rolled metal on board the ship could have slid during a storm and sunk the ship," said Pyotr Osichansky, head of the Far East Association of Sea Captains. "In that event, the cargo ship could have sunk quickly, leaving no traces on the surface."
The area is not notorious for pirate attacks.
The boat, with cargo capacity of 5,200 metric tons, was built in Japan in 1982. It flew a Soviet flag and was later sold to a private shipping company and registered in Cambodia.
Ships are often registered in a foreign country to cut operating costs, avoid government regulations or simply to take advantage of a country's infrastructure or diplomatic support.