'Irresponsible': Why Malcolm Turnbull's footy photo is causing a huge backlash

It seemed innocent enough ... a photo of the Prime Minister holding his baby granddaughter while watching the footy.

But Malcolm Turnbull's latest Facebook post has prompted a backlash online.

The PM was branded "irresponsible" for the photo, which showed him holding his granddaughter Alice, with a beer in his other hand at the AFL final between the Swans and Bombers at the SCG yesterday.

He captioned the image "multi-tasking".

But Facebook users were not impressed, calling the PM out for being an "irresponsible" child minder and using the opportunity to criticise him over the upcoming gay marriage plebiscite.

One person wrote: "Does anyone see anything irresponsible with an adult hold(ing) a baby and juggling a beer? And when was drinking while holding a child OK?"

The backlash continued: "I find it disgusting to see people breathing grog all over baby's but sadly I'm not surprised by Malcolm doing it."

But in response to the furore, a number of prominent Australians from journalists to fellow politicians were lining up to defend Mr Turnbull and take aim at the misplaced outrage.

"This is rubbish - let him be a grandpa," Labor leader Bill Shorten said on Twitter.

Turnbull's Facebook post, which has attracted more than 14,000 "likes", was inundated with more than 1,100 comments - and counting.

While a number slammed the PM, others defended the photo, saying there was nothing wrong with it.

One of Turnbull's followers wrote, "To me it's a nice pic of an Aussie Dad at the footy with his grandchild", while another said "good on him for being natural".