Three airsoft guns and packets of pellets were seized by the police at Woodlands Checkpoint on March 15 after they were detected by immigration officers.
The guns and three packets of pallets were found in the car boot of a Singapore-registered car driven by a Singaporean woman.
She was accompanied by a female passenger, said the Immigration and Checkpoints Authority in a Facebook post on Tuesday.
Airsoft guns, or any other guns which shoot pellets using compressed gas, are controlled items under the Arms and Explosives Act. Any person found guilty of having in his possession or under his control any such guns without a licence may be fined up to $5,000 and jailed for up to three years.
It is also an offence for anyone to import or export any arms or explosives, or any parts of arms or explosives, without a licence. Those convicted may face a jail term of up to three years and a fine of $10,000.