Taiwan has come up with new rules to improve Chinese mainland tourists' experience of the island at the same time as it opens the doors wider to its biggest source of tourism income.

Tourism operators interviewed by The Straits Times support the move, saying it would discourage price-cutting and unscrupulous operators from cutting corners in the rush to cash in on an influx of almost five million mainland visitors in total since 2008.

From May, the daily itinerary for Chinese mainland tour groups will be limited to 12 hours and 250km. Also, at least NT$500 ($17) in total must be spent on lunch and dinner each day, and no less than one-third of accommodation must be at starred hotels, the tourism bureau said on Monday.

The number of shopping stops should also not exceed the number of nights stayed, the bureau said, in a clear attempt to address mainland tourists' top gripe. Only two stops can be at shops selling pricey wares such as jade.

While the rules are not compulsory, tour agencies who comply will enjoy priority for the daily quota of the exit-and-entry permit for mainland visitors.

"We hope this will push the others to follow suit and thus raise tour quality for Chinese mainland  visitors," tourism bureau spokesman Lin Yan-mei said.

The daily quota for the permit has been set at 4,000 since the start of 2011 and is expected to be raised to 5,000 later this year.

Since Taiwan opened its doors to Chinese mainland tourists in July 2008, China has overtaken Japan as the island's biggest source of inbound tourism dollars. In 2011 (the latest year for which complete data is available), nearly one-third of Taiwan's six million visitor arrivals came from the Chinese mainland and they contributed $3.8 billion of the total $11 billion in revenue that year.

But the island's tourism infrastructure has struggled under the surge in influx.

Lin noted that top attractions such as the National Palace Museum and Alishan are perennially overcrowded. Tour coaches and train tickets have become scarce and accidents happen frequently. In January, a popular restaurant in Taitung county was found to have served leftovers to a Chinese mainland tour group.

The top complaint among the tourists is too much shopping - averaging one stop a day on the standard eight-day itinerary.

Of the average $266.35 each mainland traveler spent a day in 2011, 61.54 percent went to shopping. By comparison, Japanese tourists spent only 28.64 percent of their average daily expenditure of $430.53 on shopping.

Industry observers have blamed less than desirable standards on mainland tour operators that snap up a large chunk of fees paid by tourists even before they reach Taiwan. Taiwanese operators also complain of late payments by their mainland partners.

Chou Ying-chang of Teco Travel Service, which charges Chinese mainland tourists NT$28,000 to NT$35,000 for an eight-day package "to maintain standards", said of other agencies: "Tourists are taken to craft, jewellery and watch shops and stay there for two or three hours. Where is there time to sightsee?"

Lin Chien-hsing of Set Tour said he has heard of operators which charge only $20 per person a day. Both managers welcomed the tourism authorities' move to upgrade quality.