As thousands of supporters gathered near the court in Laksi district, the judges rejected her explanation she was suffering from vertigo after her lawyer failed to present a medical certificate.
The court also ordered the seizure of her B30-million bail bond.
Ms Yingluck yesterday told her supporters via Facebook to stay at home today and not go to the court.
Reports said she was last seen when making merit at Wat Rakhang Kositaram in Bangkok on Wednesday (Aug 23).
The Supreme Court's Criminal Division for Holders of Political Positions was set to announce its ruling on Ms Yingluck, who faced trial for dereliction of duty in failing to halt her government's loss-ridden, corruption-plagued rice-pledging scheme, despite being warned repeatedly to do so.
The offence carries a maximum penalty of 10 years jail and/or a fine of B200,000.
The court postponed the reading of its judgement to Sept 27.
Deputy Prime Minister and Defence Minister Prawit Wongsuwon said Ms Yingluck’s absence was not due to any mistake by security authorities. She had many residences and vehicles.
“It is not certain if she has fled or not. But she is a former prime minister, some officials may have lent her a helping hand,” Gen Prawit said.
“She may be really ill. The court issued the arrest warrant, so we must look for her,” he said.
Police estimated about 3,000 of Ms Yingluck's supporters showed up near the Supreme Court this morning.
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