Former US Defence Secretary Robert Gates is set to publish his memoirs next week and Australia's former prime minister does not go unmentioned.

In what is tipped to be an explosive account of his time as Defence head under two presidents, Dr Gates recalls a trip he took to Australia in February 2008.

Dr Gates, who was Defence Secretary from 2006 to 2011 and also a former CIA director, describes how he had slipped on ice outside his house a week before the journey, breaking his shoulder in three places.

He notes that while he was lucky that the shoulder didn't need surgery, it still caused some "awkward moments" during his travels.

"At a very nice dinner given in my honour by Australian prime minister Kevin Rudd, I was doing fine at table conversation until Rudd began a long soliloquy on the history of Australia. I had made it just past World War I when the combined effect of a painkiller, jet lag, and a glass of wine caused me to fall asleep," Dr Gates writes.

"This led to not-so-subtle attempts by my American colleagues at the table to rouse me."

Despite the nap (and the former Prime Minister's notorious temper), Dr Gates said that Mr Rudd was "very gracious about the whole thing".

His travelling party was less so. "They took raucous delight in making fun of my undiplomatic snooze."

While Mr Rudd may not be happy about having the whole world find out about his boring conversation, he got off a lot more lightly than US President Barack Obama - who is accused of not believing in the US strategy in Afghanistan.