Hong Kong - China has stopped issuing short-stay visas to foreigners at its border with Hong Kong as security is tightened ahead of the Olympics, a news report said Tuesday.

Travel agents quoted by the South China Morning Post said the practice of issuing short-stay visas at the border had been halted with immediate effect.

News of the curb comes two days after it emerged China has stopped issuing multiple-entry visas to foreigners travelling in and out of Hong Kong until after the Olympic Games.

Business people and tourists who make regular trips to mainland China from Hong Kong can now only apply for single or double entry visas.

Before the ban, foreigners could get multiple-entry visas for up to three years to visit mainland China from Hong Kong. Multiple-entry visas are widely used by business people and traders.

No explanation has been given for the crackdown on foreigners visiting China but it comes at a time when the country is restricting access to western regions amid protests over Tibet.

Tuesday's South China Morning Post quoted a spokeswoman for the Office of the Commissioner of the Chinese Foreign Ministry in Hong Kong saying the changes were due to "computer system upgrades."

Travel agents said they had been told that the issuing of multiple-entry visas for foreigners going to China would not be resume until October.(dpa)