Hong Kong's tourism chief wants tougher rules for visitors from the Chinese mainland who are coming to the country to stock up on baby formula.

The move comes amid growing hostility from some Hong Kong residents over visitors from the mainland buying up milk formula, leading to a local shortage.

Mainland tourists make up between 60 and 70 per cent of visitors to Hong Kong.

The chief of Hong Kong's tourism board, James Tien Pei Chun, has told Radio Australia's Connect Asia program only a small number of those visitors are causing problems.

"We're very concerned about the general impression that we do not welcome mainland tourists," he said.

"We want to separate the true tourists - that when you come shopping... you buy a little bit of everything, and not come and buy [only] one category of item which creates a shortage in Hong Kong."

Parents believe it is safer to buy the product in Hong Kong after several health scares involving contaminated Chinese-made infant formula.

Infant formula is seen as a luxury gift in China and demand is expected to increase ahead of Chinese New Year.

Mr Tien says the popularity is causing shortages for the locals and headaches for importers.

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"It seems there's a shortage in southern China of this particular baby product," he said.

"So quite a few of them rush to Hong Kong as a tourist... buy six cans and try to carry it through by train - several times a day."

Mr Tien says they only want to discourage visitors making the border crossing several times a day to bring milk formula back to the mainland.

"If you are a real tourist, you should not be coming in several times... once a day is enough," he said.

"So we are proposing that maybe the permit should allow them to come once a day.

"We're [also] saying should we restrict what they can bring out of Hong Kong only on this milk product - we're trying to think of policies that are targeted to this problem, and not a blanket sweep."