A 23-year-old man from South Oropouche was held for having a gun with ammunition in the Couva district on Thursday afternoon.
The police said at around 2 pm on Thursday, WPC Mitchell-Samuel and PC Bowen of the Central Division Task Force (Area South) were on mobile patrol when they saw the suspect.
He was walking along Richard Street in Mc Bean Village.
The police saw him remove a dark-coloured object from the waist of his pants and throw it a short distance away.
The police found an Austrian-made Glock 43 pistol with a magazine containing six rounds of 9 mm ammunition.
They immediately arrested the man, who is from Partap Trace, and took him to the Couva police station.
PC Bowen is leading investigations.