China's sea level witnessed an average 2.9 mm annual rise from 1980 to 2012, leading to more marine disasters and losses, the State Oceanic Administration (SOA) said on Tuesday.

According to a report released by the administration, sea levels along the coast in 2012 increased 53 mm year on year, a peak level since 1980. The East China Sea saw the biggest year-on-year increase of 66 mm last year.

The increase in levels have posed threats to islets at low altitude, which are likely to be submerged once sea water rises, said SOA official Wang Feng, adding that the country's maritime rights and interests are under threat.

The rising sea level has also aggravated damage caused by marine disasters, including storm surge, salt tide and coastal erosion, said the SOA.

The direct economic losses caused by marine disasters in 2012 amounted to 15.525 billion yuan (2.49 billion U.S. dollars). The disasters led to 68 casualties, said the SOA.

The gross ocean production totaled 5.0087 trillion yuan in 2012, an increase of 7.9 percent year on year, accounting for 9.6 percent of the gross domestic product in 2012.