He was giving an update on the progress of its investigation into the deal proposed by the Royal Thai Navy.

The Navy, he said, had studied and compared specifications and quality of submarines from various countries before deciding to buy the vessel from China.

Navy bosses proposed to purchase three Yuan-class S26T submarines from China before the Cabinet approved the purchase of one submarine worth Bt13.5 billion.

The deal was inked last Friday amid speculation over its worthiness and necessity. The Auditor-General’s office has stepped in to see whether the submarine justifies the state budget.

Pisit said initially the set budget of Bt36 billion for all three submarines was acceptable because it is was managed in a long-binding manner, thus not exceeding the Navy’s normal budget. Each instalment would cost around Bt700 million to Bt2 billion.

He said the government-to-government deal is positive to Thailand as it helps guarantee that the Chinese government would be responsible if any flaws were found on the submarines. Pisit added that such a deal should not violate the new charter’s prohibition of any international agreements deemed to affect sovereignty.

The Auditor-General’s office, he said, would continue investigating the deal signed and the budget allocation.