The road race world champion heads an impressive line-up for his Bora-Hansgrohe team, which also includes British rider Peter Kennaugh and Irish sprinter Sam Bennett.
Kennaugh will make his debut in Bora-Hansgrohe colours after making the switch from Team Sky for 2018. The Manxman proved in 2016 that kicking off his season in Australia suits him as he won that year's edition of the Cadel Evans Great Ocean Road Race.
Although Sagan's form is an unknown going into the first race of the season, it is likely that the Slovakian will be in the mix during sprint stages with Bennett as a solid back-up. He will face competition from the likes of Italian sprinter Elia Viviani, who makes his debut for Quick-Step Floors in the race.
German sprint powerhouse André Greipel (Lotto-Soudal) and Australian hope Caleb Ewan (Mitchelton-Scott) are also among the top-level fastmen taking part.
Tour Down Under race director Mike Turtur commented: "We expect another aggressive showing at the race from Sagan. Seven years ago we saw Sagan attack over the last climb on Willunga Hill finishing fifth, battling it out alongside Cadel Evans, Alejandro Valverde and Luis Leon Sanchez.
“The race and the fans are in store for something special again when he tackles the climb this year.”
Along with Sagan, Bennett and Kennaugh, Bora-Hansgrohe's line-up consists of Daniel Oss, Maciej Bodnar, Rüdiger Selig and Jay McCarthy. The latter will spearhead the team's hopes of a high overall placing, having finished third on general classification in 2017.
Last year's Tour Down Under was won by Richie Porte (BMC), who returns to defend his title in 2018.
The six-stage race commences on January 16 and finishes on January 21, and is preceded by a short criterium race in Adelaide - the People's Choice Classic - on January 14.
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