ANDREW ROBERTSON, PRESENTER: Couriers say they're set to benefit from a consumer backlash against Australia Post.

This week the postal giant increased its parcel prices by up to 30 per cent.

Online businesses say they're now shopping around for delivery services, as Emily Stewart reports.

EMILY STEWART, REPORTER: Donna Kelli runs a thriving online business selling novelty gifts. She sends up to 200 parcels a day and spends $100,000 a year on postage at Australia Post.

DONNA KELLI, ONLINE RETAILER: There were days here before Christmas I had that many parcels that he could not even fit them in his truck. So I was getting two pick-ups a day.

EMILY STEWART: Australians spent a whopping $13 billion online last year and that's proving a bonanza for Australia Post. Profit from its parcel post and retail division jumped 20 per cent last year to more than half a billion dollars.

But it's increased its parcel prices by up to 30 per cent this week, blaming higher transport and delivery costs.

DONNA KELLI: It doesn't make sense to me. It just seems like greed.

EMILY STEWART: And that sparked an online backlash. 4,000 people have already signed a petition protesting the changes and hundreds of small businesses are now shopping around for other delivery providers.

DONNA KELLI: I sell predominantly on eBay and there's a very big push for free postage. And of course, you know, you have to work out your prices in advance and postage obviously isn't free, so it can kill some people.

EMILY STEWART: And that problem's delivered a bonus for some. Fastway Couriers has 700 franchises around the country. It's geared its business towards online shopping and it's paying off.

RICHARD THAME, CEO, FASTWAY COURIERS: We've certainly seen a strong increase in inquiries in the last couple of days. I think for many of them, this'll be the first time that they've looked beyond Australia Post as a solution for their business.

EMILY STEWART: Australia Post has been the deliverer of choice, offering home delivery or pick-up at the local post office. Now couriers are fighting back. Toll Group's set to offer an after-hours pick-up remarkably like Australia Post's.

News agencies are becoming Toll's new shopfronts across Victoria. Together, they've processed more than 16,000 parcels since late last year. The partnership's been so successful, it's now rolling out across the country.

Courier companies are counting on massive growth over the next few months fuelled by customer dissatisfaction. But as competition hots up, Australia Post remains very much the major player. It's investing $2 billion over four years, promising to deliver a better parcel service.