"You now need a copy of your travel ticket both in and out of the country and a hotel voucher before they accept a visa application.
Without that they will reject it," said Daryl Bending, a travel consultant with Concorde Travel.
"I think it will deter a lot of people from travelling to China. They will just think it is too hard.
"
Another agent said visitors from 33 countries -- including India, the Philippines and Indonesia -- were no longer allowed to apply for China visas in Hong Kong and would have to apply at their local Chinese embassies.
"It is becoming more and more serious, it is really out of control," said the travel agent, who did not want to be named.
She said that tourist and business visas were also now coming back later and later, leaving travellers waiting around for hours to find out whether their applications had been accepted.
A statement on the website of the Chinese Foreign Ministry in Hong Kong said that there had been a "recent drastic rise" in the number