The World Health Organisation says more than 30,000 people in Fiji are living with depression.
The agency says stressful events such as last year's Tropical Cyclone Winston have made people more vulnerable to the illness.
Winston was the worst storm in Fiji's recorded history, killing 44 people and leaving thousands in makeshift shacks and tents.
WHO's representative for the South Pacific, Corinne Capuano, said people in Fiji had showed remarkable resilience following the cyclone.
However Dr Capuano said prolonged and acute stress could make people more susceptible to depression, the Fiji Times reported.
"For anyone suffering from depression in Fiji, you are not alone and there is no shame in asking for help," she said, speaking at a World Health Day commemoration in Suva.
Dr Capuano said 30,568 Fijians suffered from depression.
Fiji's Health and Medical Services Minister, Rosy Akbar, said 20 people in Fiji had committed suicide in the past three months while 25 attempted to take their own lives.
The ministry had launched a toolkit to help health professionals recognise, prevent and treat depression.
It had also created a second kit for teachers and education professionals.