PM accused of breaching royal etiquette

Prime Minister Tony Abbott has been accused of taking his love of Britain's royal family one step too far by daring to touch Prince William.

Harper's Bazaar posted a photo to its Instagram account depicting Mr Abbott with his hand on the prince's back in Canberra on Thursday.

The photo, which has now been deleted, racked up hundreds of likes and comments from people criticising Mr Abbott's touchy-feely approach.

His flagrant breach of etiquette was immediately compared to a similar one committed by former prime minister Paul Keating in 1992.

He put his arm around Queen Elizabeth's back when she visited Australia, causing a storm in the British press and earning him the nickname "Lizard of Oz".

Though the British monarchy's official website notes there are "no obligatory codes of behaviour" when meeting a member of the royal family, traditional protocol dictates that one keeps one's hands off at all times.

"You don't kiss them, you don't touch them, you bow — over and over again," London historian Dr Kate Williams told the BBC after the Obamas also fell afoul of protocol.

"[The royals] are treated as people set apart from the rest of us, so primarily what it is creating is distance and grandeur."