In an awkward moment that has generated significant amusement on social media, Mr Shorten showed he'd either rarely gone to Bunnings for breakfast on a weekend morning or just liked doing things a little differently to the rest of us.

Mr Shorten was at Strathfield North Public School in western Sydney and soon regretted the decision to tackle the sausage sandwich, it appeared. The Opposition Leader later turned away from the cameras as he grappled with the snag.

Mr Shorten is campaigning in Western Sydney today, handing our how-to-vote cards at a number of booths, before returning to Melbourne later to do to lodge his own vote.

Taking advantage of a media vacuum left by Prime Minister Malcolm Turnbull - who voted early and will not be seen again until election night - Mr Shorten  again characterised Saturday's vote as a "referendum on Medicare".

"Australian voters understand that you can have Malcolm Turnbull or you can have Medicare, but you can't have both," Mr Shorten said.

"People are aware that a vote for me and for Labor [means] we can protect Medicare as we know it now."

He compared Mr Turnbull to a "mugger whose taken your wallet promising not to rob you again" on Medicare.

Commenting on recent polls that have the election race tightening, Mr Shorten said Labor was "closing at the right time".

Mr Shorten mingled with voters at Bennet Road Public School in Colyton in the bellweather seat of Lindsay where Labor candidate Emma Husar is attempting to wrest the seat of Liberal Fiona Scott.

Earlier, Mr Shorten handed out how-to-vote cards for Labor candidate Angelo Tsirekas at North Strathfield Public School in the hotly-contested seat of Reid.

Reactions to his sausage sizzle troubles varied between the cruel, the confused and the potentially helpful.

"Bill Shorten's advisers on approach to next sausage sizzle: 'Remember, start from one end, mate, from one end'," Jason Scullin tweeted.