A lawsuit against Canadian music superstar Avril Lavigne may have a limited chance of success, according to an entertainment lawyer.

On Wednesday, 70s bubblegum pop duo the Rubinoos filed a lawsuit against Lavigne over her hit single "Girlfriend" because they claim it sounds like their song, "I Wanna Be Your Boyfriend."

The Rubinoos' 1979 tune features the chorus with the lyrics "Hey, hey, you, you, I wanna be your boyfriend.'' Lavigne's "Girlfriend" features the lyrics "Hey, hey, you, you, I don't like your girlfriend.''

"Copyright infringement is really about the melody and or the lyrics. And in this case I'm hearing some similarities between the two," entertainment lawyer Dave Steinberg of law firm Heenan Blaikie told CTV's Canada AM.

"There's definitely a similar look and feel between the two compositions. I don't know that there's enough there for copyright infringement however."

Tommy Dunbar and James Gangwer, the songwriters behind the Rubinoos record, filed suit in California's Northern Federal District Court and named Avril Lavigne Publishing and Lavigne's songwriting partner Dr. Luke as defendants in the case.

Their lawyer Nicholas Carline accused Lavigne of making substantial copies of the song.

"She's made a lot of money off of my client's song,'' Carlin told the Canadian Press.

"The entire song is not the same, they have different bridges, but the heart and soul of her song is directly taken from our client's song.''

In response to the allegations, Lavigne's manager Terry McBride said the legal claims are "an unfortunate part of this business.'

"Avril's very, very sensible," McBride told the Canadian Press. "She knows music well. If the chords had been similar, the melodies had been similar, lyrics had been similar ... she would have gone, 'OK, I can see their point.' But nothing's similar.''

McBride hired a musicologist when he first learned of the allegations six weeks ago and said that the results were favourable to the Lavigne camp.

"This one came back so solidly on our side it's just ridiculous,'' he told the Canadian Press.

"We will try and settle for costs that will be less than defending,'' he said. "Emotionally, it sucks. But at the end of the day you have to take that out of it.''

However Steinberg was surprised by McBride talking about settling out of court in his comments.

"If I were representing her, I would probably be saying my client has a massive amount of credibility and legitimacy as a songwriter," Steinberg said. "She does not steal and anybody who wants to sue us can come and try to take a shot and we will defend it vigorously," Steinberg said.

The allegations by the Rubinoos came just a day after fellow labelmate and Canadian artist Chantal Kreviazuk said in an interview with Performing Songwriter that she would never work with Lavigne again.

Kreviazuk, who had worked extensively with Lavigne on her sophomore album "Under My Skin" said she had noticed the punk artist had included a song entitled "Contagious" on her latest album "The Best Damn Thing" and she had not been credited.

According to Kreviazuk, she had sent Lavigne a song called "Contagious'' two years ago.

Kreviazuk however also indicated in the interview she was not intending to take legal action.

"Song titles do not have as much intellectual property protection, really if any, that let's say a full-blown song would have," Steinberg said.

Steinberg did however indicate it may have been 'discourteous' of Lavigne not to inform Kreviazuk of her intentions to use the song title, but a lack of specificity would hurt any legal claim.

"It doesn't have the same identifiable qualities that, let's say a big Beatles song would have, or "Gone With the Wind" as a film title would have," Steinberg said.

With files from the Canadian Press