JULIAN Assange's mother has hung up the phone on 3AW radio host John-Michael Howson after he taunted her with a Nazi slogan when she backed out of an interview.

Christine Assange was due to speak to the Sunday morning show on 3AW, owned by Fairfax Media, about her son, the founder of whistleblower website WikiLeaks, and his successful appeal for asylum in Ecuador.

John-Michael Howson and Christine Assange.

But she changed her mind after hearing how Howson had treated a previous guest.

''I won't be doing an interview with you because you're acting like a pig,'' Ms Assange said.