Levels at some rivers, particularly along the Caroni basin, are currently near the threshold.
This warning comes from the Met Office which expects more rainfall in the coming hours.
It has now issued a yellow level riverine flood alert until 3pm tomorrow.
In it, the Met Office warns that there is a moderate risk to public safety, livelihoods and property as watercourses may overtop their banks.
A yellow level adverse weather alert is also in effect until 6pm today.