The three major Arab groups - Yemenis, Jordanians and Syrians - have all complained of neglect or harassment in different guises, which they say makes them feel unwelcome.

One Syrian businessman who tried to check into a four-star hotel in the city a week ago was turned away. A staff member said the Public Security Bureau had told the hotel last month only to accept Middle Eastern guests vouched for by recognised trading companies.

A Yemeni businessman said: 'This is discrimination but I have not heard of complaints from Yemeni friends. If this is true, we can complain to our embassy.'

Arab businessmen have also complained of 'inspections' by police carrying cameras at restaurants and cafes frequented by customers from the Middle East.

This comes after the US consul issued a warning last month of possible terror attacks on Americans in Guangzhou.

One frustrated businessman who is having problems securing work permits for his Arab staff said: 'If they don't want Middle Easterners here, [they should] announce it. Give clear instructions. Tell us, 'We don't want you', and we will go.'

However, a Chinese source familiar with Beijing's policy on the Middle East said Arabs issued visas were safe while those who could potentially cause trouble were on a blacklist and not allowed to enter the country.

'We welcome them with open arms even if they are not big businessmen. We can't say all is absolutely safe, but we won't lock the door because of a few people,' the source said.

He said Yemeni traders got into trouble because they did not understand mainland laws and customs, and local procedures did not provide for individual businessmen to meet government officials.

Arabs say they have a big community in Thailand and that the Thai government and people treated them better, but they are believed to face more discrimination in Japan.

A University of Hawaii professor of Asian Studies, Dru Gladney, said Chinese in general were biased against Muslims and uninformed about the Middle East.

'They are suspicious and they look down on people with dark skin, so if you are not a high-ranking official you are neglected. You are an unnecessary nuisance,' he said, adding that the problem was probably more serious in Guangzhou because the local government may not follow central government policy.

Dr Gladney faulted the authorities for not doing enough at national level to tell people there were good Muslims and bad Muslims and that the majority of Muslims in China were not troublemakers.

Arabs say they feel neglect even though their ancestors started visiting Guangzhou centuries ago and built the Guangta Mosque, the earliest surviving mosque in the country and one of the holiest Muslim shrines.

There is room for only 5,000 believers to perform Friday prayers at the city's four mosques and then only if they use every bit of space inside and outside the prayer halls.

Guangta Mosque is tilting and cracking in 48 places. It was built for 300 worshippers but 2,000 squeeze in and during the twice-yearly China Export Commodity Fair the crush can be so great that they spill out onto the footpath.