"The approval was a bold move," said vice-president Niyom Waiyaratpanich. "The presence of SEZs along five border checkpoints will not only boost border trade, but also tourism, investment and the movement of labour."
He predicted Thailand's border trade would grow by 7-8% this year from last year's 924 billion baht.
To stimulate border trade in the second half of the year, Mr Niyom called on the junta to extend working hours at border checkpoints to midnight from the current 4pm and speed approvals of visa on arrival for commuters and tourists.
According to the chamber, Thailand's border trade with neighbouring countries grew by 5.7% in the first five months of the year to 405.25 billion baht.
Border trade with Malaysia contributed the most with 215 billion baht, followed by Myanmar with 81.6 billion baht, Laos with 62.3 billion baht and Cambodia with 46.3 billion baht.
The National Council for Peace and Order last Tuesday approved SEZs for Sadao in Songkhla, Mae Sot in Tak, Khlong Luek in Sa Kaeo, Khlong Yai in Trat and at Mukdahan.
The junta also approved 300 million baht to expand the checkpoints at Sadao in Songkhla province, Mae Sai in Chiang Rai, and in Sa Kaeo and Mukdahan.
The money will come from the 2.575-trillion-baht fiscal 2015 budget, the draft of which was approved by the junta last Tuesday.
For fiscal 2015 beginning Oct 1, the state is expected to run a budget deficit of 250 billion baht, some 50 billion higher than the Budget Bureau had estimated.
The investment budget will amount to 451 billion baht or 17.5% of the total, up by 8.98 billion baht from fiscal 2014.
Investment will go mainly to logistics, road improvements and expanding border checkpoints.
The fiscal 2014 budget stands at 2.525 trillion baht, with revenue collection of 2.275 trillion, leaving a deficit of 250 billion.
The main infrastructure projects involve highway construction (60 billion baht), rural road development (40 billion baht), water resource development (7.21 billion baht) and water management to prevent flooding (42.1 billion baht).
The junta also last week approved 910 million baht for 11 dual-track railways.
According to Mr Niyom, the recent meeting of the Joint Public-Private Consultative Committee chaired by Gen Prayuth Chan-ocha agreed to set up three subcommittees on privileges, labour and infrastructure.
Once the five new SEZs are in place, border trade at the Sadao-Padang Besar checkpoint is expected to rise to 500 billion baht from an estimated 330 billion baht now, he said.
Border trade via Mae Sot, meanwhile, is expected to increase to 50 billion baht from 46 billion baht, with Khlong Luek trade rising to 100 billion baht from 59 billion baht and Mukdahan trade doubling from 30 billion baht now.
Projected figures for border trade via Khlong Yai were unavailable.
The estimated figures exclude spending by neighbours who are expected to travel more via those checkpoints.
"The SEZs should be offered the highest promotional privileges from the Board of Investment, on a par with those now given to the southernmost border provinces, and facilitate cross-border labour mobility and the transport of raw materials within neighbouring countries," Mr Niyom said.
"More importantly, a linkage with the SEZs of neighbouring countries will benefit Thai industries."