The 31-year-old Briton did not take part in this year's Tour Down Under, which Porte won ahead of Colombia's Esteban Chaves, and said it was premature to be talking about who the main contenders would be in France in July.
"It's still very early obviously in the season and it's probably too early to be talking favourites for the Tour," Froome was quoted as saying by the Australian Associated Press.
"I've always had a lot of confidence in Richie's abilities and always said he's a Tour de France contender," the Briton added of his former Team Sky team mate.
With three Australians -- Porte, Jay McCarthy, and Nathan Haas -- in the top four of the Tour Down Under, Froome anticipates a strong challenge from local riders, especially over the steep Chalambra climb that marks the finishing circuit.
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"Certainly for Sunday, I'd expect Richie to be up there on that final climb, as I'd expect Esteban, and Nathan to be hanging on for dear life," he added.
"Every edition will be different but the organisers have done a great job of putting in a course that is so unpredictable. It is just a very open race."
Froome will head into the five-day Herald Sun tour, which races around northern Victoria and begins in central Melbourne with a prologue on Feb. 1, after Sunday's race.
(Reporting by Simon Jennings in Bengaluru; Editing by John O'Brien)
