IT WAS a soggy start to the Great Victorian Bike Ride in southwest Victoria.

More than 5000 cyclists and volunteers braved thunder, lightning and heavy rain at Portland to kick off the eight-day ride, the biggest supported one-week cycling holiday in the world.

But spirits were high among the cyclists, who relished the wet track for the 53km loop to Cape Bridgewater.

Event director Nikki Tyler said there were few hiccups, with hopes of drier weather over the next week.

Over the next week the ride will cover 550km across the southwest along the Great Ocean Road to Geelong.

The ride finishes next Sunday.