Despite the economic slowdown, renewed political stability has boosted demand for Bangkok office space from multinational companies, according to property consultant CBRE Thailand.

Nithipat Thongpun, executive director and head of office services, said the stable political situation raised demand significantly during the past 12 months, with the momentum set to continue in the second half of 2015.

"No political crisis is likely, as the government is on the right track in handling the political issue and it understands well what business wants," he said.

"As soon as the political situation is not in a bad condition as happened during late 2013 to early 2014, office demand will be strong."

He termed political stability the key to restoring foreign investors' confidence and drawing more investment.

"No matter how attractive tax incentives will be or how good the government's policy is, they are not enough to build up confidence and draw foreign investors," Mr Nithipat said. "Only political stability matters."

At the end of June, there were 8.4 million square metres of office space in Bangkok, up 86,000 sq m in the first half, which saw the opening of two new office buildings, AIA Sathorn Tower and Bhiraj Tower.

Overall net take-up rose by 4.8% year-on-year to 100,000 sq m. The vacancy rate remained unchanged at 9.7% but is forecast to drop to 5% in the next few years because of limited new supply.

Average rents continued to increase by 4-10% year-on-year in every grade and every area. Average Grade A in the central business district was 870 baht per sq m per month, while the highest rent was 1,200 baht at Park Ventures Ecoplex on Wireless Road.

Compared with the region's financial centres like Hong Kong and Singapore, office rents in Bangkok were lower at 900 baht per sq m. The other two locations had rents of 7,000 and 2,400 baht, respectively.

"Future office supply is limited because very few developers are buying land plots for new office development," Mr Nithipat said. "With high land costs and lower office rents, condo development is more profitable."

Just 340,000 sq m of office space under construction in Bangkok is scheduled to be completed between the second half of 2015 and 2017. This supply will include Gaysorn Tower 2 at Ratchaprasong intersection.

Some 40% of new office supply under construction in Bangkok is in the Ratchada/Rama IX area, including G Land Tower, the Stock Exchange of Thailand's new head office and Rungrojthanakul 4.

In the next five years, office supply will come from Charoen Sirivadhanabhakdi's TCC Group in locations such as Sam Yan, the site of the former Suan Lum Night Bazaar and Rama IV Road near the current headquarters of the Stock Exchange of Thailand.

Other new office buildings will include the Singha Complex on New Phetchaburi Road, to be completed in 2018, and the 125-storey Super Tower on Ratchadaphisek Road, slated to become the country's tallest building, in 2020.

Lack of new office supply means that even if quarterly take-up does not increase or falls due to weak economic conditions, occupancy levels will remain high.