Whether subway riders in this eastern metropolis will have to pass through inspections at all stations next year is still open to question, but the security checks will stay in place until the end of this year, after Expo 2010 Shanghai closed on Sunday, city metro authorities have said.

Shanghai has been doing subway security checks since May 1 when the Expo opened and all subway stations in the city are equipped with X-ray scanners. There are 6,000 people working in security on the 11 metro lines.

Over the past six months, some security checks had been slightly modified several times to cut lengthy waits, especially during rush hour.

Fast lanes at busier stations are available to passengers who are willing to open their bags for manual inspection during rush hour. People can also have their bags checked by a portable scanner.

Despite the modifications, many people complain that the security checks are inconvenient and time-consuming. Some even question the reasons for so much security equipment and so many inspectors.

"I often see the inspectors chatting with each other or playing mobile phone games instead of watching the X-ray scanner or doing a manual check," complained Xiong Liwen, who often commutes between the North Xizang Road Station and People's Square Station on Line 8.

"If they're not doing their job seriously, the checks are useless and a waste of the taxpayers' money," he said.

Other riders, however, feel safer thanks to the X-ray scanners and applaud any long-term method to guarantee public safety.

"I think security checks improve safety and, anyway, if we have little or no luggage, it takes little time to pass through the security check," said Chen Wen, who rides the subway every day.

Meanwhile, in Beijing, the first city in China to employ subway security checks - something it did for the Olympic Games in 2008 - passengers are still having to deal with them, even though the Games are long gone.