BEIJING, March 28 (Reuters) - China's farm ministry on Thursday clarified its rules on imports of transgenic foods and raised traders' hopes that Sino-U.S. soybean trade, worth $1 billion a year, could soon recover from suffocation by red tape.

The Ministry of Agriculture told a training seminar on genetically modified organisms (GMO) that foreign firms did not have to apply for as many safety permits for their GMO products as originally thought under China's current, temporary rules.

"Foreign exporters do not need to apply for separate safety certificates for each cargo, as long as they have applied for the same type of GMO products and it involves the same exporters and buyers," a ministry official told the seminar in Beijing.

They also did not have to apply for GMO labels for their bioengineered products, ministry officials told the seminar.

Foreign firms in China welcomed the news and said they were confident some importers would get safety permits in about a month, possibly kickstarting U.S. soybean shipments which had stalled for about nine months due to confusing GMO rules.

Some traders dashed off after the seminar to use mobile phones to enquire about soybeans, hoping that a bureaucratic logjam would now clear.

"I think some companies would dare to start to ship soybean cargoes to China now after the meeting," said a trader from a global trading firm.

"People are now more sure that they can get safety certificates in about a month's time," he said.

While foreign firms cheered, Dalian soy futures fell slightly on worries new imports could dent demand for the domestic crop, traders said. The front-month May contract ended seven yuan lower at 2,152 yuan ($260) a tonne.

Red tape and confusion

The seminar cleared up confusion about the procedures needed to import GMO soybeans into China that had remained even after the Chinese government earlier this month temporarily relaxed unclear rules which had been issued last year.

In this month's relaxation, which resulted from a deal with the United States, China announced temporary safety measures for GMO imports that would last until December 20.

The temporary measures included reduced paperwork and a shorter approval time of up to 30 days, down from 270 days, for the safety certificates needed to import GMO soybeans.

About 70 percent of U.S. soybeans are transgenic.

On Thursday, traders welcomed the ministry's guidance on how to apply for import permits. The two-day seminar was attended by about 500 people including industry officials and crushers.

"The procedure for the interim period is simpler than what we had expected. Now we just need to fill in the form and wait for their approval," said a trader at a global trading firm.

Dalian soybean futures fell on Thursday on worries that imports might hit demand for the domestic crop, traders said. The most active July futures ended at 2,102 yuan, down 13 yuan.

The contracts have been in backwardation since early this week as China faced an imminent shortage of soybeans if fewer foreign cargoes arrived and as the domestic crop ran out, traders said.

"But so far, Dalian's falls are capped because no one has obtained approval on the safety certificates yet," said a futures trader from a domestic brokerage in Beijing.