He was due to appear at the Department of Special Investigation (DSI) to hear the charge against him for falsely declaring the price of luxury cars to avoid high import duties.
His representative said the 36-year-old could not attend to hear the charge at the DSI as he was preoccupied preparing documents to explain himself against the charge.
The alleged offence taken place in 2013-2014, said Panusak's representative.
DSI chief Pol Colonel Paisit Wongmuang said that Panusak was within his rights to ask for a postponement, which the agency would normally grant an accused person once during the investigation.
Paisit also said the Customs Department was slated this month to give the DSI a calculation of unpaid taxes linked to the second batch of 300 luxury cars that had been seized.
Last month, Customs officials informed the DSI that the unpaid taxes linked to the first batch of 30 Lamborghini cars was Bt650 million.
Paisit said three accused executives of Niche Cars Group, the country's leading high-end distributor of luxury cars, had already acknowledged the charge of faulty car-import declaration, which was filed based on 28 invoices allegedly carrying faulty information.
The DSI raided Niche Cars Group's showroom in May and seized 60 cars for inspection on suspicion of tax avoidance.