Online retail sales are continuing to strengthen, with Australians spending more than $15 billion over the internet in the past year.

The National Australia Bank’s online retail sales index grew 12.5 per cent in the year to March as Australians spent $15.2 billion shopping online.

Growth was strongest for groceries and liquor while department and variety stores and fashion also saw strong growth, the report said.

Media continued to trend downward while daily deals and personal and recreational goods also contracted.

Sales growth in traditional bricks and mortar retail had also improved in recent months, the report said.