UPDATE 3-Frontline says roughly 80 mln bbls oil stored at sea

(Adds oil trader comment)

By Stefano Ambrogi

LONDON, Jan 16 (Reuters) - Norway's Frontline (FRO.OL: Quote, Profile, Research), one of the world's biggest oil tanker owners, said on Friday oil firms were storing "about" 80 million barrels of crude oil at sea, possibly the highest in a quarter of a century.

The figure is the highest storage estimate reported to date. Ship broking houses, banks that trade oil and other industry sources believe the total is considerably lower.

"We think it's about 80 million barrels...but we are not 100 percent certain," the acting chief executive officer Martin Jensen told Reuters by telephone from Singapore.

Crude freight rates have been supported on top export routes by the slew of storage bookings. Tanker firms' profits are tied to the underlying cost of oil freight.

Mike Wittner of Societe Generale said the Frontline figure fitted the broader oil market picture.

"It's a big number, but its entirely plausible -- I don't see any reason not to believe him," Wittner said, adding the upshot was storage is significant and could easily grow even more.

Jensen said some 30 to 35 Very Large Crude Carriers (Very Large Crude Carriers) capable of carrying two million barrels each and 10 Suezmaxes with a capacity of a million barrels each were being used by oil firms for floating storage in the last few months.