Dan Tantisunthorn, head of research at Jones Lang LaSalle, said the apartment market in central Bangkok had continued to perform well, with average occupancy standing at more than 90 per cent, driven by strong demand from rising numbers of expat residents.

Based on the number of work permits issued, increasing numbers of expats are residing in Bangkok.

The number of permits rose from 47,107 at the end of 2004 to 54,607 at the end of last year.

During this year's first half, this figure grew another 5 per cent, to 57,343.

The increasing influx of expats has continued to sustain healthy performance in the apartment sector despite higher competition with condominiums for rent.

Dan said competition was likely further to intensify, because more condominium projects were scheduled for completion in the next few years.

The Jones Lang LaSalle's study indicates this year will see a total of 34 new condominium projects with more than 7,600 units completed in central Bangkok.

While the ratio of owner-occupied to rental units is difficult to estimate across the market, the company anticipates 25 per cent of the units in a completed condominium building are being offered for rent.

He said that would serve the strong demand for regular and serviced apartment in a market where supply is lower than demand.

Theerathorn Prapunpong, associate director of residential leasing services at CB Richard Ellis, said most expats tended to rent rather than buy property in Bangkok, because in many cases Thailand would be only a temporary posting, maybe two or three years.

As a result, the rental market has grown in Bangkok.

He said the largest growth had been in the Japanese community, which now accounts for 22 per cent of all foreigners with work permits in Bangkok.

Theerathorn said the market trend had prompted his company to believe that 30-40 per cent of new expat-standard condos available for rent had been bought by investors who would now be seeking tenants for them.

Prime locations for regular and serviced apartments and condominiums available to tenants are Sukhumvit Sois 1-63 and Sois 2-44, the Lumpini area and Sathorn Road, research by both CB Richard Ellis and Jones Lang LaSalle indicates. Sukhumvit Road, especially around Sois 24 and 39, is becoming increasingly popular, especially among Japanese tenants, mainly due to easy access to the subway and the Skytrain routes.