Australia Post has launched one of its most significant delivery programs in recent years, Shipster, ahead of the arrival of internet juggernaut Amazon.

The move, which will offer free delivery, will be welcomed by local retailers who are preparing for the increased online shopping competitions.

Shipster works in a similar way to Amazon Prime, where customers pay a small monthly fee, but get many delivery benefits. Already 40 Australian retailers have signed up to Shipster.

According to Australia Post, online shopping has grown from 11.5 per cent to 15 per cent in the past 12 months, and the service is predicting the busiest year for online shopping "we've ever seen at Australia Post".