Australian comedienne Rebel Wilson's musical comedy Pitch Perfect 2 has topped the North American box office with a record haul, but George Miller's Mad Max: Fury Road also made a mountain of cash.

The original Pitch Perfect film was a sleeper hit in 2012 with a quiet $US5 million opening in the US and Canada before becoming a DVD and digital download sensation with teenagers.

Pitch Perfect 2 earned an astonishing $US70.3 million from Friday through to Sunday - more than the original made in its entire 2012 run in North America and achieving the highest-ever debut for a musical.

The film stars Wilson, Anna Kendrick and Hailee Steinfeld as part of a US college a cappella group.

The sequel opens with Wilson accidentally flashing US President Barack Obama and First Lady Michelle Obama while performing on a trapeze at New York's Lincoln Center.

"It is a very flashy opening I would say," Wilson told AAP in an interview.

Mad Max: Fury Road, the fourth film in the franchise, had a strong $US44.4 million opening to finish second.

Supported by strong reviews, American audiences didn't mind the 30-year gap since the last movie, Mad Max Beyond Thunderdome, or that Mel Gibson didn't reprise his role as the post-apocalyptic warrior.

Mad Max: Fury Road had Englishman Tom Hardy in the title role, Oscar-winner Charlize Theron as his co-star and instead of the Australian outback, it was shot largely in the western African nation of Namibia.

"It's a film where there's a lot of applause at the end of the movie," Dan Fellman, Warner Bros domestic distribution chief, told Variety.

"A lot of people coming to the movie went purely on the reviews."

Avengers: Age of Ultron, which debuted on May 1, continued to rake in millions with a third-placed $US38.8 million finish, taking its North American total to $US372 million.

The major bomb on the stellar box office weekend was the critically-panned Reese Witherspoon-Sofia Vergara comedy Hot Pursuit that earned a poor $US5.8 million.