Ninety million baht's worth of brand-name products were seized in tax evasion cases between last October and last month, the Customs Department says.
The value represents a 50% rise on the same period the previous year, according to Chaiyut Khamkhun, the department's spokesman.
The department released the figures after a Thai Airways International flight attendant was arrested as she attempted to smuggle in several untaxed brand-name products.
Following a tip-off, customs officials arrested the flight attendant who was found to have brought in goods exceeding the allowance limit. She had been on a THAI flight from Italy.
Several brand-name products, including belts, were found concealed under her clothing.
Mr Chaiyut insisted cabin crew and air passengers are treated equally when it comes to searching and prosecuting people trying to smuggle goods into the country to evade import tax, he said.
Those caught smuggling face a fine of four times the value of the contraband products, plus import duty, he said.
Mr Chaiyut said about 90% of people caught agree to have the smuggled products confiscated to avoid paying a hefty fine, he said.
Each year, more than 30,000 contraband cases are handled by the authorities. If every one had to be settled in court, the judicial system would likely buckle under the excessive workload, he said.
Imposing fines to settle these cases helps ease the burden on courts. However, fines are not an option in some cases such as the smuggling of items governed by the Convention on International Trade in Endangered Species of Wild Fauna and Flora (Cites) and electronic waste, he said.
The government has a duty to abide by the Cites regulations and implement policies to safeguard the environment, he said.
The total value of all contraband, including illicit drugs, the department has seized in a total of 29,875 cases between October last year and August this year stands at 2.62 billion baht.
He said the most common items smuggled both in and out of the country are narcotics.
Cars, auto parts, medicines, cosmetics are among the key products from which the department collects import tax, he said.
The department recently struck cooperation agreements with Hong Kong, South Korea and Singapore to improve customs clearance protocols, he said.
The department is negotiating similar deals with Malaysia, Australia, Japan and China, he said.