Chinese submarines are well-suited for developing nations' navies, as they boast strong combat capabilities, proven technologies and competitive prices, according to industry insiders.

"Our conventional submarines are not as technologically advanced as the best ones, but their capabilities are good enough for regional naval powers, and they all have a reasonable price," said Cui Yiliang, editor-in-chief of Modern Ships magazine.

"In the past, Chinese-made submarines have had some defects in design, materials and production techniques. However, we have begun to catch up," he said, urging Chinese shipbuilders to develop more cutting-edge technologies.

"Our submarines will become popular in the international market once Chinese engineers make more breakthroughs in key technologies such as the air-independent propulsion system."

Zhang Junshe, a senior researcher at the People's Liberation Army's Naval Military Studies Research Institute, said it is difficult to compare Chinese submarines with their Russian or Western counterparts because they haven't released the full specifications of their submarines, which are a major backbone of naval deterrence.

"The advantages of Chinese submarines are their reliable performance, which have been tested and proved through long service with the PLA navy, and their competitive price," Zhang said. "Top equipment is good, but I don't think a developing country's navy actually needs the best-equipped and most expensive submarine. Ours are good enough."

Foreign media recently reported that Pakistan is close to inking a multibillion-dollar contract to buy eight attack submarines from China, which could be the most valuable weapons export China has made to date.

Sources from Pakistan's navy told the Financial Times that the decision for the arms deal was made "in principle" at a recent meeting of the National Assembly Standing Committee on Defense. The price and type of submarine being pursued was not disclosed.

A former senior Pakistani navy officer with knowledge of the negotiations told the British newspaper that the contract could be worth $4 billion to $5 billion.

Pakistani Prime Minister Nawaz Sharif has approved the deal, and the vessels "would be used to bolster Pakistan's strength", Reuters quoted an unnamed Pakistani official as saying. Some Pakistani officials have come to China to discuss issues concerning the purchase, the source said.

Pakistan is considering purchase of the Type 039A-class diesel-electric submarine or its export variant, the S-20, the source said.

zhaolei@chinadaily.com.cn