Temasek and Singapore officials have said the deal complies with Thai law regarding foreign ownership.
Last month Temasek said it would cut its stake in Shin Corp "at the appropriate time".
But on Thursday, Temasek said it would not sell its shares until the interim government clarified its interpretation of foreign ownership rules.
The military-backed government has vowed to crack down on corruption but has come under fire for taking pay raises and installing its own people in top posts at state firms.
Senior security officials on Thursday said they expected the military government would lift martial law in December, once corruption probes against Thaksin were completed.