The private sector has made a renewed push for the central bank to contain the baht's rapid gain after a recent 25-basis-point cut of the policy rate had almost no effect on the local currency relative to regional peers.
The Joint Standing Committee on Commerce, Industry and Banking (JSCCIB) called on policymakers, the Bank of Thailand and the Finance Ministry to limit the baht's strength quickly to maintain the country's competitive edge, Supant Mongkolsuthree, chairman of the Federation of Thai Industries, said after Wednesday's monthly meeting.
The policy rate cut has not stopped the baht's appreciation, which is taking a toll on exports, tourism and foreign direct investment, Mr Supant said.
"Additional measures may be needed to cope with the stronger baht," he said. "Those measures include imposing a withholding tax, outbound investment promotion and tapering the bond supply. These are ultimately the regulators' decisions."
In the year to date, the baht is 10% and 14% stronger than the Chinese yuan and South Korean won, respectively, while the Vietnamese dong has been stable versus the US dollar.
The baht has surged by about 6% against the greenback this year, making it the best-performing currency in Asia.
According to the Bank of Thailand's Monetary Policy Committee minutes for the meeting on Aug 7, there was concern that the baht's gain relative to trading partners' currencies could affect the economy to a larger degree amid intensifying trade tensions.
The central bank started to rein in short-term offshore fund inflows by reducing its new short-term bond supply.
It then stepped up efforts by lowering the cap on the outstanding balance of non-resident accounts from 300 million baht per person to 200 million baht and requiring a report with the names of end beneficiaries for all non-resident holdings of Thai debt securities.
Mr Supant said the private sector is gathering data from businesses on the baht appreciation's effects for further discussion with regulators.
The baht is expected to continue strengthening if the US Federal Reserve further eases its monetary policy as anticipated.
The JSCCIB wants to take part in a fiscal and monetary committee initiated by Deputy Prime Minister Somkid Jatusripitak to help policymakers seek ways to boost the economy, Mr Supant said.
Predee Daochai, chairman of the Thai Bankers' Association, said the firmer baht will dampen the country's competitiveness amid the slowing economy and the ongoing trade spat between the US and China.
Thailand's economic growth is likely to come in lower than the JSCCIB's current forecast range of 2.9-3.3%, he said. The joint committee is set to trim the economic and export growth estimates again at October's meeting.
The JSCCIB predicts the country's outbound shipments this year to perform in a band of 1% contraction to 1% growth.
The joint committee said economic momentum in July likely remained sluggish, as seen by the contraction in exports if gold is stripped out.
Domestic consumption was still tepid in July, while investment was stable.
The government's stimulus package could offset impacts from negative factors surrounding Thailand, but it will take time for the government's planned measures to attract foreign relocations, the panel said.
Meanwhile, Thai Chamber of Commerce chairman Kalin Sarasin said business operators have managed to tackle foreign exchange risks by themselves through baht settlement on intra-Asian trade, especially with Cambodia, Laos, Myanmar, Vietnam and Australia.