Supermaxi LDV Comanche has taken the lead on the first day of the 73rd Sydney to Hobart yacht race after a dramatic start in Sydney Harbour.

At 7.40pm AEDT, Comanche led Wild Oats XI heading south near Batemans Bay.

The other favourites, last year’s line honours winner InfoTrack (formerly Perpetual LOYAL) and Black Jack, which had earlier taken the lead, were trailing in third and fourth place respectively.

Just minutes into the race, Comanche appeared to wave its red protest flag after a near collision with Wild Oats Eleven heading out of Sydney Harbour.

It is understood no formal protest has yet been lodged with the race committee.

Thousands of people lined the banks of the harbour to watch the start of the 630-nautical mile race at 1pm AEDT.

More than 100 yachts, including 27 international entries, are making their way down the New South Wales south coast and across often treacherous Bass Strait on their way to Tasmania.

A favourable weather forecast of 15 to 25 knot north-to-north easterlies into Wednesday has led to predictions that the race record – set by Infotrack (racing as Perpetual LOYAL) last year at one day, 13 hours, 31 minutes, 20 seconds – might be at risk.

-ABC/AAP