The makers of children's toy Barbie have lost their legal appeal over a song which mocked the blonde doll.

The US Supreme Court upheld a previous ruling dismissing Mattel's lawsuit against MCA Records Inc over the 1997 pop hit Barbie Girl.

Mattel claimed the song, by Danish pop act Aqua, infringed on the toy maker's trademark and sullied Barbie's reputation.

But appeal judges dismissed the lawsuit, saying the song was "parody" and "social commentary" covered by the US constitution's free speech protections.

The ruling is another blow for Mattel

Aqua stormed the charts with the song, in which a female singer portraying Barbie refers to herself as a "blonde bimbo" and says "life in plastic, it's fantastic".

She is also enticed to "go party" by a male singer representing Ken, Barbie's plastic boyfriend.

Mattel had argued that the song, which sold more than 1.4 million copies in the United States, could confuse consumers and dilute the power of the Barbie brand.

But MCA defended the song as "social commentary", saying the album Aquarium featured a disclaimer noting the song was not sanctioned by the maker of Barbie dolls.

Mattel appealed to the Supreme Court after losing its initial case in July last year.

But the appeals court and a federal judge in California determined the song's title was not misleading and that consumers would not be confused.

Parody

The news comes as another blow to Mattel - the world's largest toy maker.

This is the third case it has lost over the Barbie mark in two years.

In February 2001, a court ruled that an American artist was within his rights to use Barbie dolls in his work.

Some of Tom Forsythe's photographs depicted the blonde in sexually compromising positions.

A court had ruled on that occasion too that parody of Barbie was an acceptable activity.