The number of tourist arrivals can be expected to top 50 million a year by 2015, according to a forecasting system set up by the Polytechnic University's School of Hotel and Tourism Management.

And those tourists will spend HK$201 billion.

The world's first web-based tourism demand forecasting system also sees mainland tourist numbers doubling to 8.59 million in 2015, with their spending topping HK$90 billion.

Demand by mainland tourists for high tariff hotel rooms is expected to peak near 12,000 by the second quarter of 2015.

That would be a more than twofold increase in the demand for guesthouses - from around 1,500 this year to just over 4,000 by 2015.

Project leader Song Haiyan, chair professor at the school, unveiled the system - available on subscription - at the university's Li Ka Shing Building yesterday.

He said the system is unique among computer-generating models because the results are scrutinized and adjusted by a panel of 12 experts.

"If we only rely on the econometric model to generate forecasts, it is too rigid and cannot incorporate possible future events," Song said.

"The system cannot incorporate information regarding the 2008 Beijing Olympic games because there is no historical data.

"But experts can input their forecasts to adjust the econometrics and take into account future events. It is the unique feature of the system."

With historical data, government statistics and representatives from the government, academia and the industry, the system is able to generate forecasts for tourist arrivals, demand and expenditure on food, retail transportation and hotel rooms.

Song said the system can also generate ad hoc forecasts such as attendances at major theme parks provided there is historical data.

The system, he added, would provide vital planning information for the industry's decision makers and government policymakers.