FOR THE executive traveller staying at Hongkong's best hotels, there are plenty of bargains to be had, even though the hotels are not suffering a shortage of business. To attract the high-spending businessman, the leading hotels are generally prepared to offer special incentives which can work out very much to the benefit of their expense account. The JW Marriott has launched a new ''Rates of Exchange'' programme, which allows guests to move up one room category, while paying the lower room rate. The hotel's marketing director, Kent Maury, said if a guest booked and paid for a daily rate of, for example, $1,750 for a mountain-view room, that room would automatically be exchanged for an executive floor mountain view, valued at $2,050. Extra attractions include round-trip limousine transfers, daily breakfast, late check-out, and up to two suits dry-cleaned during the guest's stay. ''We are off to a great start in 1993 and, as the industry and the economic environment maintain positive growth, we will continue to look after the long-term prospects and interests of our clients,'' he said. The neighbouring Hotel Conrad has what it calls a Business Bonuses Programme, which is a year-round feature. When a guest books into a room as part of this scheme, he will enjoy an automatic upgrade to a higher room category, or to a suite. The scheme also includes daily breakfast, complimentary dry-cleaning and laundry service, late check-out to 6 pm, and limousine transfers. A guest booking into a superior Peak-view room for $1,800 would, therefore, be upgraded to a deluxe Peak-view room at $2,000; and a deluxe harbour-view at $2,450 becomes an executive floor harbour-view at $2,800. However, summer is the time when the business traveller can take advantage of some of the hotel packages which are, essentially, designed for the leisure market, but which can offer attractive savings. The Hilton, for example, is offering a three-night package to celebrate the hotel's 30th anniversary. At an all-in cost of $3,999, plus 10 per cent service and five per cent tax, the guests have a deal which includes daily buffet breakfast, champagne, fruit, chocolates, a welcome drink, and use of the health club. The Island Shangri-La, meanwhile, is offering a special summer programme, which prices a Peak-view room at $1,300 per night and a harbour-view room at $1,610. A minimum of two consecutive nights is required. The executive floors, which most hotels in Hongkong are now offering, are an interesting option for the executive traveller on a budget who may worry about the scrutiny his expenses may undergo back in the office. Most of the executive floors offer a breakfast, to which a guest can invite business contacts. Most also offer free drinks in the evenings. ''For the hotel operator, it is a matter of getting the education right, and not making a loss,'' said the general manager of the Holiday Inn Crowne Plaza Harbour View, Gerhard Hecker. ''But what we are finding now is that with budgets in Europe and the US being tighter, it actually makes good economic sense for many executive travellers to stay in executive-floor rooms. ''For us, they are proving highly successful - the occupancy levels are generally higher than that of the hotel itself.''