Two robots are even attached to the ceiling and can serve dishes from up above, placing dishes of food on tables.

"The robot restaurant is a modernization revolution in the catering and serving industry. It's a meaningful and an irresistible trend to introduce robots into people's daily lives, as it can save on manpower and increase fun during meals," said Liu.

A robot greets customers in a robot themed restaurant in Harbin, capital of Northeast China's Heilongjiang province, Jan 18, 2013. Opened in June of 2012, the restaurant has gained fame by using a total of 20 robots to cook meals, deliver dishes and greet customers. [Photo/Xinhua]

Humans are needed in the restaurant but only to assist the robots.

"After seven months in operation, the restaurant is recognized and is welcomed by our customers. We also keep improving the robots' functions and work efficiency, as well as increase the variety of dishes," said Liu.

Some are concerned though.

"Zuohongbo", wrote on Sina Weibo, a popular Chinese micro-blogging site, "It's a newfangled thing, and I'm happy to know that we have so many advanced technologies. But what worries me is it will be more difficult to find a job, as robots will compete with human beings in the future."

Liu said his team is developing a "human-robot interaction function", so that children will be able to play games with the robots.

Haohai is not the first robot restaurant in China. In December 2010, Dalu Robot restaurant opened in Jinan, capital city of East China's Shandong province.

With rapid development of science and technology, China has seen an increasing number of robots being used in various fields, including industry, agriculture, medicine, security, the military, police and the service sector.