The Central Asian pipeline network, launched in 2009, spans about 2,000 km (1,250 miles) from Turkmenistan, Uzbekistan and Kazakhstan before reaching China's northwestern Xinjiang province.

"We can start shipping our gas right now, but there are some legal issues which need to be settled," Tulagan Zhurayev, head of Uzbekistan's state-controlled gas transportation firm Uzbektransgas, said on the sidelines of the international Oil and Gas of Uzbekistan conference.

"We haven't started shipping gas yet," he said. "We plan to supply this year between 2 bcm and 4 bcm. We have the gas and everything is ready." Earlier, Uzbekneftegaz officials said that the gas supplies will start to China on 1 April 2012.

Zhurayev declined to comment on the figure. "Supplies are definitely set to expand next year, but so far a more realistic talk is about between 2 bcm and 4 bcm this year," he said.