Brigitte Barèges, an MP in French president Nicolas Sarkozy’s ruling UMP party, has sparked an angry reaction in the French parliament by comparing gay marriage to bestiality.

The 58-year-old MP from Montauban was speaking at a debate to open marriage to same-sex couples across France.

She appalled fellow politicians by exclaiming: “So in that case, why not unions with animals? Or polygamy?”

Felllow UMP MP Franck Riester called Ms Barèges’ comments “disgraceful and degrading”. The leader of the UMP party, Jean-François Copé, added: “These unacceptable comments naturally in no way reflect the UMP’s position.”

Left-wing MPs have called for Ms Barèges to withdraw her comments and make a public apology.

Christophe Girard, the deputy mayor of Paris, said the comments were “pathetic and vulgar” adding that Ms Barèges is “unknown to the French, is doubtless seeking publicity … What will be her next struggle? That there are too many Chinese on the planet, that transsexuals make her laugh? The most idiotic Right in the world has just shown its true face.”

Ms Barèges refused to apologise but said: “I meant it as a joke, and I am personally in favour of all types of sexual relations between consenting adults.”

Later in a statement, she said she had decided “withdraw the clumsy remarks which she contests are of a homophobic nature”.

In any case, the proposed law on same-sex marriage was rejected on Wednesday evening.