Is it okay to throw an apple core out your car window?

Tempers flared on The AM Show on Monday morning as hosts Duncan Garner and Mark Richardson butted heads over whether it was acceptable to dispose of natural materials on the roadside.

While Richardson was quite strongly against it, Garner didn't think it was so bad - and fellow host Amanda Gillies agreed with him, as long as it was into the bush.

"I've had some arguments with certain people who will throw an apple core out the window," Richardson began.

"Well that's okay, isn't it?" Garner responded.

"No it's not. They'll say, 'Oh, it's biodegradable', but it sits around and looks ugly for a while before it might actually eventually go somewhere.

"Put it in the rubbish or down your waste disposal unit, and respect this country.

"I don't care if it's biodegradable - before it disappears to nothing, [an apple core] is rubbish."

Garner then gave fellow host Amanda Gillies the task of finding out how long it takes for an apple core to completely decompose - and when he found out, he admitted he was "astonished".

Both an apple core and banana peel takes about one month to decompose, while orange peel takes about six months.

While that may seem a long time to some, non-natural materials take far longer to decompose; cigarette butts take between 10 and 12 years, and plastic bottles and bags take centuries.

"Oh, well the apple's fine to throw out then," Garner said, upon hearing how long plastic takes to break down.

But Richardson was having none of it.

"It's sitting around for too long," he said. "It's making this environment and this country look like a tip and it's unacceptable."