Australians are expected to spend about $10 billion on food over the Christmas period, but a staggering 35 per cent will be wasted and end up as landfill.

Food rescue group Oz Harvest, which collects leftover food and distributes it to charities, says it will pick up about 150 tonnes of food throughout December.

Oz Harvest founder Ronnie Khan says the group is distributing to more than 400 charities and welfare agencies.

She says waste increases significantly at this time of year.

"From mid-October to the end of December, we call this our harvest period," she said.

"It's the time to collect as much as we can, because there's an abundance of food being shared around with those people who have.

"I just got a call that there's 75 kilos of dark chocolate, magnificent dark chocolate which will be beautiful as part of hampers.

"We're collecting the equivalent of around 140 to 150 tonnes a month - that's just in Sydney. That's about 20 tonnes more than usual."

Oz Harvest driver Marcel says the increase in food waste is not just coming from homes but from businesses holding Christmas parties and other festive events.

"There's more waste at this time of year probably than at any other and that's because as we approach Christmas, everyone likes to party, everyone likes to have more food, more drink, and that's both the corporate sector and many small businesses," he said.

"That means that for Oz Harvest, it's a very busy time for pickups, but it's also a very busy time for deliveries because all the charities want to make sure the people they serve and the people they support are able to participate in the festive season and not miss out because of financial or other hardship.

"So it's a special time for us and we do the very best we can to pick up as much food as we can and get it as quickly as possible to the charities and into the hands and the mouths of those that need it."

Planning ahead

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The shocking level of waste is of great concern to environment group Planet Ark.

It says every year Australians generate about 361 kilograms of food waste per person.

Planet Ark recycling programs manager Janet Sparrow says 35 per cent of food is expected to be wasted this month.

"There's a lot of food waste being thrown out, and we've got a lot of room for improvement over this period," she said.

Ms Sparrow says there are a number of things people can do to reduce their food waste this Christmas.

"Planning ahead is a really key part of reducing food waste, and also thinking about your leftovers - what you're going to do with your leftovers after the big feast, how you're going to store them and whether you're going to share them with you friends and family that you're celebrating with," she said.

"They're really key things that you can do this Christmas to reduce your food waste."

Planet Ark has launched an education campaign to encourage Australians to think about how they can reduce their environmental impact over the festive season.