BEIJING (REUTERS) - A riot at a major airport in China by passengers angry about delays caused by heavy snow has marred the end of the traditional week-long Chinese New Year holiday, state media said on Friday, as millions rush to return to work.

Passengers at Zhengzhou airport, capital of the populous northern province of Henan, stormed check-in desks and smashed computers and other equipment after the airport closed for more than five hours due to the snow on Thursday, newspapers reported.

Pictures on China's Twitter-like Sina Weibo microblogging service showed police trying to calm angry crowds and broken signs at airline counters.

"There were not enough seats, and passengers had to sit on their luggage eating instant noodles. The airport staff were indifferent and said 'I don't know' to questions asked of them," Henan radio said on its microblog. The Global Times, a tabloid published by the official People's Daily, described the incident as a "riot". It added that the airport finally reopened late on Thursday.

New year is China's most important traditional festival - for many the only holiday of the year - and is marked by a mass migration as people flock home to spend it with families, crowding trains, buses and aircraft.

Domestic media frequently reports on incidents of passengers angered about delays attacking airline staff, storming onto grounded aircraft and destroying equipment.

The government has told airlines and airports to better explain the causes of delays and to provide free hotels and food, but the airlines complain the problem is rooted in an inexperienced travelling public which is still not used to problems associated with flying.

Air travel is booming in China on the back of explosive economic growth, driving huge orders for foreign aircraft manufacturers and an ambitious airport building scheme taking in some of the country's most remote areas. However, service standards have failed to keep up, many travellers complain.