A race-record contingent of five supermaxis, four of them previous line honours winners, will contest this year's Sydney to Hobart yacht race.

A week before entries close, 80 boats have already nominated for the annual 628 nautical mile race starting on Boxing Day on Sydney Harbour.

Included in the fleet will be the supermaxi quintet of Comanche, Wild Oats XI, InfoTrack, Black Jack and Scallywag.

All those boats bar Scallywag, the only non-Australian supermaxi of the five, have taken line honours in the race at least once, though some won under a different name.

Hong Kong's Scallywag was the only one of the five not to contest the race last year, though it was third across the line in 2016 and has another third and a second on its record from previous years.

Confirmation of the supermaxi contingent sets the scene for a mouth-watering battle given the controversial outcome of last year's race.

Eight-time line honours winner Wild Oats XI reached Hobart first ahead of Comanche in race record time

But their positions were reversed after an international jury upheld a protest from Comanche, following a near collision between the duo on Sydney Harbour shortly after the race start.

The two boats lined up against each other in the Sydney to Gold Coast race back in July, but both were beaten to the line by light wind specialist Black Jack.

Last year's Sydney to Hobart overall winner Ichi Ban will be back, and the Matt Allen-owned TP52 will be challenged by several other well-performed mid-sized boats.

The 2018 fleet will also include at least 12 overseas yachts.

Organisers expect the fleet to swell to around 85 to 90 boats by the close of entries next Friday.