China's first aircraft carrier, Liaoning, is likely to have its preliminary trial on the high seas this year, a necessary step before it possesses full combat capability, said the vessel's commander-in-chief of testing on Tuesday.

"Before every aircraft carrier truly matures and becomes capable of fighting in a war, it must go through trials on the high seas," Zhang Yongyi, the commander, who is also a deputy to the National People's Congress, told China Central Television.

On Saturday, the vessel moved from China's northern port of Dalian, where it was retrofitted and later commissioned, to the port of Qingdao. Prior to that, Liaoning had undergone 12 sea trials. Carrier-based fighters also completed take-off and landing tests on Liaoning late last year.

A trial on the high seas is much tougher than Liaoning's previous tests, because it requires the carrier to be fully independent of on-shore protection, said Lan Yun, editor of Modern Ships, a magazine run by a research institute related to the shipbuilding industry.

"During past trials, if an accident happened, on-shore experts could immediately help out because the vessel was not too far away," Lan told the Global Times. "But on the high seas, crew members must solve the problem themselves."

Liaoning had traveled hundreds of kilometers away from China's coast before. But this time, Lan said, it may have to reach waters near Japan's Okinawa Islands and even Guam, both located more than 1,000 kilometers away from Qingdao.

Such trials often require a vessel to remain at sea for one to three months, he said.

If Liaoning's first high seas trial is successful, many more will follow, Lan said. That means the vessel may take another two years before reaching its full fighting capacity, he added.