Online retail giant Amazon more than doubled profit over the past year, smashing analyst expectations as it revealed plans to speed up shipping times of its products.

On Thursday afternoon US time, the company said it booked $US59.7 billion ($85.1 billion) in sales in the first three months of 2019. First-quarter net income soared 125 per cent from a year ago to reach US3.6 billion, its highest profit ever.

Presenting the earnings result in a conference call, Amazon's finance chief Brian Olsavsky said the company was working to overhaul its default Prime delivery to get products to customers in just one day.