Wholesale and retail price for petrol and kerosene will decrease by 6.47 seniti/litre and 0.64 seniti/litre.
Diesel prices are almost the same, up by 0.18 seniti/litre.
The change, which came into effect Monday will continue until Monday, 17 June.
A government statement said crude oil price movements were mixed last month with upward pressure in response to escalating tensions in the Middle East and downward pressure from lower economic forecasts due to the US-China tariff war.
The freight rate has reduced.
However, the weaker Tongan Pa’anga has offset some of the change in product prices within Tonga.