A flood warning is in place for most of Solomon Islands after up to 150 millimetres of rain fell in 24 hours.
More rain is forecast for the week ahead and people in low lying areas are being warned to take precautionary measures and stay away from rivers and streams.
The situation is caused by a monsoon trough that is moving eastwards across the country.
A second low pressure system is also forecast to strike in the next few days.
The Director of Meteorology, David Hiriasia, says there is a risk that the system will develop into a cyclone as it moves towards the earthquake and tsunami affected Temotu province before moving on to Vanuatu.