The weather office has upgraded the heavy rain alert to a heavy rain warning as of Monday evening.
The warning issued on Monday was current for Choiseul, Western, Isabel, Malaita, and Guadalcanal Provinces.
The warning stated that a low pressure system lies over Solomon Islands and slow moving.
Associated clouds with rain and thunderstorms are expected to affect the Solomon Islands.
People living close to rivers, streams and low lying areas were therefore strongly advised to take precautionary measures because of flash flooding or flooding which may pose danger to lives and property.
Motorists were also advised to use extreme caution when travelling in these areas.
Never attempt to cross rivers and large streams of unknown depth.
The office will continue to issue updates today.