We have all been there: at work, the clock edging towards home time when your concentration drifts, your eyes edge shut and head starts to bob like a cork in a slipstream.

This afternoon it was the Deputy Prime Minister, Nationals leader Warren Truss, appearing to doze off.

And he could not have been in a worse position for it to happen: the front row, right behind Prime Minister Malcolm Turnbull in direct line of the main television camera in the chamber.

Mr Truss had been sitting on the plush, green leather chairs of the House of Representatives for more than an hour during the last Question Time of the week.

Mr Turnbull was answering a question about the ABC's coverage of the National Broadband Network, casting our minds back to the 2013 election campaign.

"We counted and said we can get the thing, the project built, the network built faster and at less cost by using a mix of technologies," Mr Turnbull said.

Mr Truss had been glancing down at his phone for much of the afternoon's proceedings.

But when his eyes appeared to shut and his head began to slowly bounce around, attention on him began to intensify.

Mr Truss was elected as the Member for Wide Bay in 1990 and this term is widely tipped to be his last.

He was sitting to the left of Nationals deputy leader, Barnaby Joyce, the man expected to replace him as leader.

After a short time Mr Truss glanced up at his deputy, and nodded as if to say "yep, I'm awake".

Perhaps, after a big sitting week in Canberra, there have been more exciting times to be an Australian.