The German boat Illbruck has moved to the front of the pack as five Volvo round-the-world vessels battle for the lead in the Sydney-Hobart race, after the front-runners crossed Bass Strait in a race dominated by violent storms and a tornado.

Only four nautical miles separated the first four boats at a scheduled early-morning radio position report on Friday, with the leaders likely to cross the finish line in Tasmania on Saturday morning.

Race officials said the first five boats, illbruck, Tyco, News Corp, djuice and Assa Abloy, were near Flinders Island off the northeast tip of Tasmania with about 220 nautical miles of the 630-mile race remaining.

Pre-race favorite and defending champion Nicorette of Sweden was in sixth place and making up ground slowly after the fleet battled strong southwesterly winds of 25-30 knots in Bass Strait between mainland Australia and Tasmania. Eight state-of-the-art Volvo-class 18-meter boats are competing in the 630-nautical mile Sydney-Hobart as part of the third leg of their race around the world.