“The Thai Navy requires submarines to maintain a military balance in the region because other neighbouring countries already have them. It will help protect our sovereignty, as well as our abundant marine resources, notably in the Andaman Sea,” Prawit said.

The Navy proposed buying three Chinese-built submarines for a total of Bt36 billion. The plan features the acquisition of S26T diesel-electric submarines, which are modified export versions of the Yuan-class (Type 041).

The first submarine will cost around Bt13.5 billion under fiscal budget 2017, according to the Navy. The annual budget was approved in a fiscal bill last September.

However, the procedures of the deal appeared a bit confused. Prawit said Cabinet had not received the final plan, but Navy spokesman Chumphon Lumpikanon said the plan had already been approved in accordance with the Prime Minister Office’s regulations of procurement.

The Navy has to propose the budget plan to Cabinet, which endorses it and asks for approval from Parliament. But the NLA reported that it had already approved the plan in the annual budget bill in September.

“Now, we are considering details on the equipment to be installed in the submarine,” the spokesman said, noting that the Chinese producer would take six years to build the vessel.

Local security experts are split on the whether the Navy needs a small fleet of submarines as maritime threats are not perfectly clear. Some analysts say buying surface vessels would be a better defence strategy.

Wanwichit Boonprong, a security expert at Rangsit University, said the purchase might be financially questionable as the cost was twice as much as HTMS Chakri Naruebet – an aircraft carrier purchased 20 years ago that has seen little use, although it is still regarded as strategically worthwhile amid a rise in maritime threats in the Asia Pacific.

He highlighted tension in the South China Sea involving China and nations in Southeast Asia such as Vietnam, saying the purchase would enhance the country’s naval capabilities and could be deemed a deterrent |against possible maritime threats or bullying.

Wanwichit agreed that military purchases “can be made way easier under a [military-installed] government than under a civilian government – under which the Army could only buy second-hand and outdated equipment.”