Canadian singer Avril Lavigne has strongly denied accusations that she has plagiarised other artists' work.

Last week a lawsuit was filed by two American songwriters, alleging her single 'Girlfriend' sounds like a song called 'I Wanna Be Your Boyfriend', which was released by California-based pop band the Rubinoos in 1979.

The 22-year-old star fired back in a letter on her website, saying "I had never heard this song in my life and their claim is based on five words! All songs share similar lyrics and emotions. As humans we speak one language."

Lavigne's manager, Terry McBride, called the suit "baseless" and little more than a "case of legal blackmail."

"Avril's a great songwriter and she's proving it over and over and over again," McBride said.

In her letter, Lavigne also said that she was considering legal action against Chantal Kreviazuk after the songwriter suggested that Lavigne had swiped one of her ideas.

"Let it be crystal clear that I have not ripped anyone off or done anything wrong," she said in the letter addressed to media, fans and friends.

"I do not deserve this negative press and attention," she said. "I take pride in the songs I write and appreciate the opportunities to work with some great writers and musicians."