BEIJING (REUTERS) - China has banned its trawlers from fishing in waters off the eastern coast of North Korea, due to a dispute over fuel supplies, the latest irritant in ties between the often uneasy allies.

North Korea decided last month that Chinese ships operating legally in its waters had to buy fuel from its suppliers rather than making their own arrangements as in the past, the Chinese government said late on Monday.

"Our fishing boat owners and companies believe this decision by North Korea will affect normal fishing operations and safety, creating risks and dangers," the government said on its main website (www.gov.cn), citing the agriculture ministry.

Waters to the east of North Korea are also especially risky due to the "complex, changeable situation on the Korean peninsula" and their proximity to Russia, Japan and South Korea, the government added.

"Many of our fishing boats operate in North Korean (waters) and if they are not properly managed or well-organised then diplomatic incidents can easily occur," it said.

The statement made no mention of Chinese boats that operate near the North's western coast.

In May, North Korea seized a Chinese fishing boat in waters off its western coast, prompting anger in China. The boat was released after a fortnight, following the intervention of China's Foreign Ministry.

Tension has been mounting between North Korea and China even though China is the North's most important economic and political backer.

Some Chinese banks have frozen out North Korea's main foreign exchange bank amid frustration in Beijing over the North's continued pushing of its nuclear weapons and ballistic missile programmes in contravention of UN sanctions.