Met Service director Arona Ngari said the heavy rain experienced on the island from Monday night was due to the low pressure system passing the Southern Cooks from the northwest.
Ngari said though this was expected to move away yesterday evening, Rarotonga would continue to experience rain.
According to the Met Office weather update, the trough of low pressure is accompanied by associated clouds and rain that remains slow moving over both the northern and southern islands.
The forecast to midnight tomorrow for the southern islands shows occasional and heavy rain and a few thunderstorms over most islands, with moderate northeast to southwest winds and rough seas.
Nagri urged road users to be cautious while driving in the rainy conditions.