Canadian punk princess Avril Lavigne is being sued by U.S. songwriters who claim her smash hit Girlfriend sounds suspiciously like a track they took up the charts in the 1970s.

Lavigne's manager, Terry McBride, said the pop starlet is one of several people named in a lawsuit filed July 2 that alleges striking similarities to the 1979 Rubinoos song I Wanna Be Your Boyfriend.

Avril Lavigne, seen here in Los Angeles in November, recently released her new album The Best Damn Thing.
(Branimir Kvartuc/Associated Press)

The group's founder, Tommy Dunbar, filed the suit in California's Northern Federal District Court. It also names Lavigne's publishing company, Avril Lavigne Publishing, and her songwriting partner, Dr. Luke, as defendants.

McBride said from Vancouver the claim is baseless, noting that a musicologist he hired to study both tracks has deemed them completely different songs.

Still, McBride, also CEO of Nettwerk Music Group, admitted he would consider settling the suit out of court if the costs of defending the case prove too high.

The suit follows a jab at Lavigne by fellow Canuck songstress Chantal Kreviazuk, who recently suggested to Performing Songwriter magazine that Lavigne stole one of her songs for the disc The Best Damn Thing.

Kreviazuk told the publication she had given Lavigne a song called Contagious two years ago, and was surprised to see a track with the same name on Lavigne's current disc with a credit to Lavigne and songwriter Evan Taubenfeld.

McBride said Kreviazuk has never even heard the Lavigne track.

"I know, personally, she regrets saying what she said," said McBride, adding the songs are nothing alike. "The interviewer obviously got Chantal on a bad day."

The hitmakers behind past Lavigne hits Sk8er Boi and I'm With You have also slagged Lavigne's writing credits.

Songwriter Lauren Christie of the production team the Matrix told Rolling Stone that Lavigne did little but "change a word here or there." Lavigne has insisted the pair crafted the melodies and lyrics together.

McBride said the barrage of criticism is just part of being at the top of the charts.

"Everyone comes after the stars. If Avril was not successful, they wouldn't really care," he said.