China has the ability to detect signals sent from deep in the sea, but the month-long hunt for missing Malaysia Airlines flight MH370 has exposed technological drawbacks in China's maritime search and rescue outfit, experts said.

Chinese patrol ship Haixun 01 picked up electronic pulsing signals in the Indian Ocean on Friday and again on Saturday. But some foreign experts are skeptical about whether China's equipment is advanced enough to obtain signals from as deep as 4,500 meters under the sea.

The ship is equipped with maritime detection equipment, including one black box sonar detector and two underwater robots, said Wang Liangyu, head of maritime survey at the Donghai Navigation Safety Administration under the Ministry of Transport.

"All of them were imported," he said. "The black box detector, which was made by the same company that produces black boxes, has a maximum detection range of 5,000 meters."

The adoption of such advanced technologies has enabled China to catch "ping" signals from the black boxes, he told Shanghai newspaper Jiefang Daily.

However, searchers need more time to analyze and verify the signals to see whether they are consistent with the black boxes - the flight data recorder and the cockpit voice recorder.

Many Chinese applauded Haixun 01's findings, but say China still lags behind other nations when it comes to maritime search and rescue equipment.

"I'm proud that it was our ship that first detected the (suspected) signals," said an Internet user who goes under the name biedong1925, "but it is a pity that none of the equipment used was made in China".

Some experts said more resources and investment should be allocated to China's maritime search and rescue outfit development.

"There are a lot of things that China should do to upgrade its equipment used in maritime search and rescue operations," said Cui Yiliang, an expert on ships and naval armament in Beijing.

"We must speed up the research and development of autonomous underwater vehicles, or AUVs," he said. "High-tech underwater vehicles such as the Bluefin-21 play an irreplaceable role in deep-sea detection and retrieval operations, but I haven't read any reports about similar equipment developed in China."