Kelly Osbourne has accused her former Fashion Police colleague Giuliana Rancic of being a "liar" and says she will only return to the show if the outgoing E! News host leaves.

The scathing comments come after Osbourne's departure from the show in February, just weeks after Rancic controversially said dreadlocked actress Zendaya Coleman looked like she smelled of "patchouli oil or weed".

The show was taken off air for several months but will return this week with Rancic and Joan Rivers' daughter Melissa Rivers as the new host.

When asked by The Wrap if she would return to the show, Osbourne said, "If certain people weren't there".

"I will never admit to liking Giuliana [Rancic] because I don't. I don't think she's a good person and I think she's a liar.

"I am so happy for Melissa that she is filling that seat and I want that show to go on. It was just my time to move on."

Osbourne reportedly warned Rancic several times during filming of the Fashion Police segment not to make the patchouli comments because Coleman was a friend of hers, a claim both Rancic and E! denied.

Rancic declined to comment on the latest outburst, telling US Weekly, "I've got to take the high road on this".

The 41-year-old stepped down as the long-running host of E! News several weeks ago to pursue other opportunities.

Earlier this month, Osbourne also came under fire for racist remarks during an appearance on US talk show The View.

When discussing Donald Trump's negative view of Latino Americans, Osbourne said, "If you kick every Latino out of this country, who is going to be cleaning your toilet Donald Trump?"

The comments immediately drew groans from The View's co-hosts, who told her "latinos are not the only people doing that".