He said he did not have the authority to extend the deadline for the tax collection period due to taxpayer rights.

“If the deadline will be extended, there is no longer a statute of limitations,” he said.

That would breach legal principles, he said, referring to the ruling of the Finance Ministry’s Tax Commission.

However, he said efforts to collect taxes from the Shinawatra family would not stop, adding that the Revenue Department had to enforce tax laws to recover due payments.

He acknowledged that tax officials in the past had tried to proceed with charges regarding assets of the Shinawatra family but the Central Tax Court had ruled against authorities.

Apisak has been caught in the crosshairs after the auditor-general asked him to exercise his authority to restart tax procedures against the family while the Tax Commission stated he could not extend the expired tax collection deadline.

The move came after the department admitted it was unlikely to collect taxes from the family regarding its controversial sale of Shin Corp shares in 2006.

This is because the five-year tax summons limit will expire at the end of this month. The admission came despite the Revenue Department being under considerable pressure from the Office of the Auditor-General.

In January 2006, Ample Rich Investment, a firm owned by Thaksin, sold 11 per cent of Shin Corp to his children Panthongtae and Pinthongta a few days before Shin Corp was taken over by Singapore government-owned Temasek Holdings in a deal worth Bt73 billion.

Critics of the controversial deal raised questions on whether the sale was liable to tax, as Thaksin’s children benefited from capital gains. Tax authorities did not collect taxes from Thaksin’s family. But the Criminal Court later jailed a number of officials involved for failing to collect tax from Thaksin’s family.

In 2012, the Central Tax Court ruled that Panthongtae and Pinthongta should not be taxed because the owner of the shares was Thaksin, and his children were only acting as nominees. The court said any tax claims would have to be made against the actual owner of the shares.