BEIJING (AFP) - Myanmar has sentenced an unspecified number of Chinese nationals to more than a decade in jail for illegal logging, China's state media reported on Thursday, saying Beijing was "highly concerned" and had made representations.

The loggers were arrested following a January crackdown on illegal forestry activities in Myanmar's northern Kachin state and sentenced to "more than 10 years in prison", state news agency Xinhua said, citing China's Foreign Ministry.

An unnamed Myanmar court official in Kachin state told AFP on Wednesday that 153 Chinese loggers had been jailed for life for illegal logging.

Xinhua's report did not specify the number of people imprisoned nor the exact sentences.

"Since these Chinese nationals were arrested by Myanmar at the beginning of this year, China has repeatedly raised representation with Myanmar from various channels," Foreign Ministry spokesman Lu Kang was quoted as saying.

"China has requested the Myanmar side to consider the actual situation of those loggers and deal with the matter in a lawful, reasonable and sensible way," he said.

Logging in Myanmar exploded under the former junta, as the generals tossed aside sustainable forestry practices in their thirst to cash in on the country's vast natural resources.

But the quasi-civilian government that replaced outright military rule in 2011 has sought to stem the flood of timber from the country with a ban on the export of raw logs that came into effect in April last year.