Argentina has introduced new restrictions on online shopping as part of efforts to stop foreign currency reserves from falling any further.
Anyone buying items through international websites will now need to sign a declaration and produce it at a customs office, where the packages have to be collected.
The procedure will need to be repeated for every new purchase.
Argentina's reserves of hard currencies dropped by 30% last year.
The government of President Cristina Fernandez de Kirchner has introduced a number of restrictions on transactions with foreign currency.
Each individual is allowed to buy up to $25 (£15) a year from abroad tax free, but it has been hard for custom officials to keep accurate records of each consumer.
Once the $25 level is reached, online consumers in Argentina need to pay a 50% tax for each item bought from international websites.
Currency controls
The government hopes that new declaration will make it easier for customs officials to enforce the import tax, says the BBC's Ignacio de los Reyes in Buenos Aires.
New currency controls were introduced a week after Ms Fernandez was re-elected in 2001.
Among the restrictions introduced more recently are a 35% tariff on any credit card transaction abroad.
Despite the government's efforts, Argentina's reserves are now below $30bn (£18bn) - their lowest level since 2006.
Currency controls, which were common in most countries until the mid-80s were dropped in Argentina in 1991. Finance minister Domingo Cavallo pegged the local currency, the peso, to the dollar.
The plan collapsed 10 years later, when the government was forced to devalue its currency.
The country eventually froze bank accounts and defaulted on its debts. It has since struggled to attract foreign loans at market rates.
Source: BBC
