Shadow Education Minister David Pisoni says he has offered to resign over a sexist slur towards Education Minister Grace Portolesi.

A draft Liberal media release was sent to a news outlet yesterday containing a sentence from Mr Pisoni that was meant to be deleted.

It was accidentally left in the release, saying if schools received a dollar for every time the education minister wore her black leather skirt, it would raise thousands.

He has apologised to the minister, and described the comment as a ‘silly, tacky gag’.

“I offered my resignation for the embarrassment it may have caused Isobel, and Isobel refused to take the resignation,” Mr Pisoni told 7News.