Foreigners pay VND120,000 (about US$6) and locals pay VND80,000 to visit the old town, which includes entrance to five major destinations.

The city added more ticket checkpoints early this month in order to limit the loss of revenue stemming from unauthorised ticket sales.

"The city started selling package tickets for tourists in 1995. It's common practice for world heritage sites. Tourists visiting destinations have to pay a fee, which goes towards conserving the heritage site and benefiting the local people," vice chairman of the city's People's Committee Truong Van Bay said. "We have not seen any protests from tourists or travel agencies about the fee. But the city's administration failed to explain it clearly and the poor manners of inspectors added to the confusion among tourists."

The vice chairman said the city hosted 1.6 million tourists last year, including 750,000 who stayed in the town. However, only 500,000 paid the entrance fee.

The city made VND76 billion (US$3.6 million) from tickets, only 80 per cent of the expected revenue. This was especially costly as Hoi An has to invest in night festivals in the old town seven days a week.

The vice chairman said some travel agencies intentionally did not include the ticket in the tour programme, so tourists had to pay for it on their own.

My Hanh, a tour operator of Da Nang-based travel agency Vitours, said her company always booked the entrance ticket for clients. However, she suggested that Hoi An administration explain the reason for the payment clearly to visitors.

"All tourists know that they have to buy tickets when visiting a world heritage site like Hoi An," Hanh said. "If tourists see a notice board saying that the ticket payment will go towards conserving the UNESCO-recognised world-heritage site, they won't mind paying a little money for their visit."

According to local visitor Ha My, ticket inspectors in Hoi An failed to send this message to tourists.

"They should gently explain the entrance fee to visitors, rather than just not letting them inside," My said.

"I also think the city should create more options for tourists. A tourist might want to wander around the old town, eat at a restaurant or buy some souvenirs, but not visit destinations like the Japanese bridge, Fujian and Jiao Zhou clubs and ancient houses and pagodas. In that case, they shouldn't have to pay VND120,000."

Pascal Daurel, a French tourist, said paying for such tickets was very common and he did not mind at all.

"It's necessary. Hoi An is a world heritage site and buying tickets is a way to contribute to conservation and restore the heritage," he said.

Vo Phung, director of the city's culture and sport centre, said that tourists might not understand the ticket policy because inspections in previous years were quite slack.

"Visitors thought that they could walk in the old town free of charge and just buy tickets if they visited the major destinations," he said. "Inspectors failed to explain the actual policy well, so visitors complained on Facebook and tourism websites."

The ticket crackdown has reduced the number of visitors to the old quarter in recent days, worrying households in the town.

"We saw more tourists in previous years, when walking around appeared to be free. I suggest that the city let tourists visit the old quarter free and just pay for visiting key destinations," said Minh Nhan, a resident in Hoi An.

Tomo Usuda, a Japanese tourist, said the strict inspections would hurt businesses like restaurants, souvenir shops and tailors.

"I think the city should offer cheaper tickets for tourists who don't want to visit sites," Usuda said. "It's so expensive to pay $6 just to walk around in the street and look at things."

Phung said residents of the old town and their friends would not have to buy tickets.

The city will host a press conference on ticket prices and inspections and other tourism-related problems on Saturday.