For sending within Australia, send parcels by Monday, December 13 for parcel post and Monday, December 20 for express post. For some locations, including Perth, Darwin and outside of metro areas, Australia Post recommends sending them earlier and to check the Australia Post website for details.

Christmas cards should be sent by Thursday, December 16.

And customers sending overseas are encouraged to do so as soon as possible as cut-off dates vary depending on the destination.

Australia Post executive general manager, business and government Gary Starr said preparations for the peak season were already well under way, including recruiting a more than 4000 Christmas casual team members - a record.

"We're seeing record parcel volumes with more than 5.9 million households shopping online a month - that's more than half of all Australian households, and it's showing no signs of slowing as we head into the online sales season and Christmas," Mr Starr said.

"That is why we've planned ahead with extra air freight capacity, weekend deliveries and recruitment of thousands of new team members to ramp up our delivery services, parcel sorting and customer care, and we'll be delivering right up until Christmas Eve.

"We encourage people to make a note of these important delivery dates, because although we'll deliver items sent after these dates as quickly as we can, they may not arrive until after Christmas."

See more at auspost.com.au/sending/christmas-sending-dates.