Retail, wholesale and hotel operators around Ratchaprasong intersection plan to allocate a combined 60 billion baht to make the area an important retail destination in Asean over the next three years.
The plan also expects to double the number of visitors and boost the location's image among tourists in the region when the Asean Economic Community comes into effect at the end of this year.
Although the country's economic recovery remains slow, Ratchaprasong business owners have continued to expand their operations.
They say the shopping area is not big enough to respond to the rising number of foreign tourists, who continue to visit every year.
Meanwhile, retailers in the area forecast that the purchasing power of local consumers will return to normal in the third quarter if the government invests in the megaprojects as scheduled.
In addition, the occupancy rate of leading hotels in the area is almost back to normal.
"About 146 million visitors shop and use services in the Ratchaprasong area each year, but when Asean becomes a single market by the end of 2015, we expect the number of visitors will increase to 200 million a year," said Chai Srivikorn, president of the Ratchaprasong Square Trade Association (RSTA).
The Tourism Authority of Thailand said 3 million tourists from China visited Thailand last year.
About 300 million Chinese tourists are expected to go abroad in the near future and Thailand is one of their favourite destinations.
Among the new investments lined up for the downtown shopping district, The Market by Platinum Group intends to invest 7.5 billion baht in 226,500 square metres of space next to Big C Supercentre Rajdamri.
Meanwhile, 5.8 billion baht will go for the development of 63,000 sq m at Gaysorn II.
Central Pattana Plc has earmarked 10 billion baht for a major facelift of CentralWorld shopping complex. Minor International Plc will spend 600 million baht to rebrand its Four Seasons Bangkok Hotel as the Anantara Siam Bangkok.
About 400 million baht will be spent to link 18 buildings in the Ratchaprasong area via a skywalk, which will be opened by the end of next year.
After the completion of these projects, shopping space in the Ratchaprasong district will increase to 1 million sq m. There will be around 150,000-180,000 sq m of new office space and another 4,000-5,000 hotel rooms, up from 3,900 rooms at present.
Mr Chai, who is also the chief of Gaysorn shopping centre, said these additions would make retailers in the Ratchaprasong area ready to compete with other major shopping districts in Asean.
After all the developments are in place, visitors can do their shopping in all retail atmospheres from luxury to wholesale to weekend markets like Chatuchak Market within the same location in one day.
"Ratchaprasong will become a shopping capital of Asean and a must-visit destination for tourists. And trading value in the area will double over the next three years," Mr Chai said.