"I don't believe that Le Pen can win," Hofer told a TV talk show late on Thursday, forecasting that Macron will win 59 percent and Le Pen -- who enjoys friendly relations with Hofer's Freedom Party (FPÖ) -- 41 percent.
Hofer, 46, said however that this could not be called a "defeat" since Le Pen -- lagging the centrist Macron by 22 percentage points in the latest opinion polls -- will still have "the best election result in history".
Hofer also took a swipe at Macron, saying: "I think that Macron in an insecure personality, he doesn't inspire much confidence. He has behaved badly, all he has done is to slander and insult Le Pen."
The Local France: French presidential election 2017
Ambivalent about the European Union and saying Islam "has no place in Austria", Hofer last year narrowly lost a runoff election for the largely ceremonial but coveted Austrian presidency to Alexander Van der Bellen, a pro-EU moderate.
Hofer's anti-immigration FPÖ, founded by former Nazis in the 1950s, successfully challenged the result in the courts but in a re-run in December Hofer lost again with 46.2 percent of the vote.
The FPÖ, headed by Heinz-Christian Strache, is riding high in opinion polls and is eyeing winning power in parliamentary elections due in late 2018 -- or earlier if Austria's squabbling centrist coalition falls apart sooner.