Blue Coolant Light On for long peroid of time

Hi.



I have a Renault clio 1.2 MediaNav 63 plate.



Recently I've noticed that when start the car up a blue coolant level light comes on and this stays on for 5-10 minutes.



Does anyone know what this means and if its a problem as when I've researched it only says its a problem if the light turns red.



Cheers