Singapore's tourism industry doesn't appear to be hurting as yet but a prolonged period of haze could spell trouble for the industry during holiday season.

It remains business as usual at Changi Airport, although the airport has increased the interval between flight take-offs and landings as an additional precautionary measure to ensure the safety of flight operations.

"Even with this added step taken, we have not experienced any significant delays in flight departures and arrivals due to the haze at this time," a spokesman for the Civil Aviation Authority of Singapore (CAAS) said in response to queries.

The airport is keeping a watchful eye on the runway visual range (RVR), or the range over which a pilot can see along the runway. The RVR was in the region of 900 metres late yesterday afternoon. A high Pollutant Standards Index (PSI) level can cause the RVR value to fall.

"At Changi Airport, we have the facilities and procedures to allow safe landing of aircraft in low visibility conditions in accordance with international standards," the CAAS spokesman stressed, adding that the airport continued operating back in 1997 during the extended period of haze even when the RVR plunged to some 800 metres.

Meanwhile, the Singapore Flyer temporarily suspended operations as a safety measure for its employees after the PSI soared to 371 as at 1pm yesterday.

"The health risks posed by the haze have led us to close the Singapore Flyer for the time being to protect staff members, many of whom work outdoors," said Tim Reid from Ferrier Hodgson, which has been appointed the receiver and manager of the Flyer. "We will reassess the situation (this) morning, and the Flyer will reopen as soon as pollution levels drop to a safe level."

According to Alicia Seah, senior vice-president (marketing) of CTC Travel, the tour agency has had to reschedule visits to the Flyer this week due to poor visibility. "You go up and you can't see anything," she told BT.

Ms Seah said that it has yet to receive cancellations from customers, although CTC Travel has received calls of concern from some customers. But as peak season approaches, it could be grey skies ahead if the haze reading remains high for a prolonged period.

"July and August is peak season for China and Indonesia. We are seeing bookings and inquiries (for travel into Singapore) slow down," Ms Seah said, adding that inquiries from markets such as China, Vietnam and Indonesia were down 20 per cent this week. Indonesia and China are the top two visitor generating markets for Singapore.

The travel agency is trying to keep outdoor activities to a minimum, incorporating visits to shopping malls and museums as part of the itinerary instead, as well as providing masks and mineral water to its tour groups.

The Royal Plaza on Scotts hotel also continues to receive reservations and enquiries, although a few guests have inquired about the haze situation, according to its director of marketing, Odette Huang.

Airlines that BT spoke to yesterday said that they are monitoring the situation. Nicholas Ionides, vice-president of public affairs for Singapore Airlines, highlighted that the airline is working closely with the regulatory authorities. "Flight operations are currently not affected but contingency procedures are in place, including diverting flights to alternate airports in the event that the haze situation worsens," Mr Ionides explained. In the meantime, SIA has released advisories to its staff on what precautions to take, in line with Ministry of Manpower guidelines.

AirAsia, which runs over 660 flights to and from Changi each week, told BT that it will "act accordingly" if customers start to give the budget carrier feedback about the haze.

AirAsia Singapore chief Logan Velaitham added: "Having said that, we welcome any travel advisories the government and authorities issue and will definitely abide by them accordingly if they do issue one."

Meanwhile, ground-handler SATS has issued N95-level facemasks to its staff, making it compulsory for those working outdoors to use them when the PSI surpasses 200.

"They are reminded of important safety protocol such as wearing high visibility safety vests for ground staff working on the tarmac and ensuring that vehicle headlights are turned on," a SATS spokesman said. A mandatory fitness test and medical assessment will be imposed for SATS employees who work outdoors if the 24-hour PSI average breaches the 400-mark.