It expects to deliver three million more parcels this December than it did last year and has hired 2000 more staff to handle the extra load.

At a warehouse the size of a football field in Alexandria, workers begin at 4.30am hauling parcels from vans to metal cages, on to forklifts and finally into large trucks. Three-quarters of the warehouse is given over to parcel packing and only a small section to Australia Post's traditional business of letters.

The ''parcel boom'' is happening because record numbers of Australians are shopping online, says Richard Umbers, executive general manager of parcel and express services at Australia Post.

About 70 per cent of parcels delivered by Australia Post are ordered over the internet.

Mr Umbers says a key change over the past year has been that many more Australians are using the internet to buy expensive gifts such as jewellery and clothes. Items costing many hundreds of dollars that in the past customers would have bought only after trying on in a store are being bought off a screen, he said.

Australia's online retail sales climbed to about $12.3 billion over the past year and are growing at an annual rate of about 26 per cent, according to National Australia Bank's online retail sales index for October 2012.

Most Australians still prefer to shop at ''bricks and mortar'' stores, but sales in such stores are growing at a comparatively sluggish 2 per cent a year, according to the same report.

Australians living in rural and regional areas were moving online to do their Christmas shopping at a faster rate than city dwellers, Mr Umbers said. ''Which makes sense, given their lack of access,'' he said.

To handle the extra parcels, Australia Post is delivering on weekends leading up to Christmas.

It has also opened a city superstore with 24-hour lockers where shoppers can collect or deposit their presents.