The Liberal candidate in the crucial Bennelong by-election is apologising after a video showing him telling racist rape jokes surfaces.

"More than 20 years ago I told crude and inappropriate jokes, which were completely unacceptable and I apologise unreservedly," John Alexander said.  "There is no place for jokes about violence against women. Again,  I apologise unreservedly."

The video of Mr. Alexander was posted on YouTube in 2011, and shows the politician in Brisbane in the 1990s, back when he was a referee on the TV show Gladiators.  He tells two jokes:  The first is about an Irishman who goes to confession to scam the priest into revealing the names of sexually-active women.  The second is about "a black guy from Chicago" who witnesses a rape.

John Alexander is contesting the seat he was forced to vacate after learning he was most likely a dual citizen by descent, and therefore unable to sit in the Federal Parliament under section 44 of the Australian Constitution.  In order to get the seat back, he needs to overcome a strong challenge from former NSW premier Kristina Keneally.  If Labor wins the seat, it puts the Turnbull government's majority at risk.

Prime Minister Malcolm Turnbull welcomed Mr. Alexander's apology: "Statements like that, whether they're intended as jokes or not, are completely and utterly unacceptable," the PM said.  "There is no place for joking about violence against women."

But Labor leader Bill Shorten took a sterner line:  "The comments are crass, they're wrong, they're stupid, and the apology is 22 years too late."