Postman Leon Craig is busy. He says he is even busier than during the Christmas period, which is usually the most frenzied time of a postie's year.

Key points: More Australians are shopping online during the coronavirus pandemic, with online department store purchases up 473 per cent

More Australians are shopping online during the coronavirus pandemic, with online department store purchases up 473 per cent Australia Post chief executive Christine Holgate said lengthy delays were due to the grounding of much of the air freight network

Australia Post chief executive Christine Holgate said lengthy delays were due to the grounding of much of the air freight network Australia Post is retraining motorbike posties to deliver and process parcels

But unlike at Christmas, there is no end in sight.

"There's a lot more parcels compared to everything else. It used to be majority letters, but now it's parcels," the 22-year-old Victorian, who works in Warrnambool, said.

"Most people are understanding; I just tell them that we're working as hard as we possibly can."

As Australians stay at home, and with many bricks and mortar stores closed, it is no surprise there has been a huge strain placed on the postal service.

Australia Post is delivering about 1.8 million parcels a day. Online department store purchases are up 473 per cent, while fashion purchases have trebled (up 203 per cent).

Australia Post chief executive Christine Holgate. ( Supplied: Australia Post )

The result has been lengthy delays to many online orders, angering Australians waiting at home on deliveries.

Australia Post chief executive Christine Holgate blamed the blow-out in delivery times on the grounding of much of Australia's air freight network.

"We were putting on to the Qantas passenger planes up to about 700 tons a week of parcels and that literally, over a few weeks, went to zero," Ms Holgate told 7.30.

Australia Post is now chartering extra planes for parcels, but Ms Holgate said that had disrupted delivery times.

"Our challenge is that when you switch [to] a chartered network from what was the scheduled network, we just can't guarantee the times that we have previously."

Delays compound sense of isolation

Bethany Kernaghan and her children were disappointed their bikes did not arrive in time for Easter. ( ABC News )

Bethany Kernaghan from Burramine in Victoria is one of those people trying to be understanding about the unprecedented wait times for parcels.

It has been nearly five weeks since she ordered two toy bikes and trailers to keep her kids occupied during lockdown.

Bethany Kernaghan's children still enjoyed themselves at Easter. ( Supplied: Bethany Kernaghan )

"I thought, you know what, for Easter, I'm going to go all out, I'm going to buy them both a bike and it's going to be happy days," Ms Kernaghan said.

"The closest toy shop that would have something similar to what I bought the boys is about an hour-and-a-half away, so online was my only option really."

After being told by Australia Post the bikes had been lost, Ms Kernaghan re-ordered them from the seller.

But she received a notification Wednesday saying the original package had arrived at her local post office. She says the seller is now out of pocket after replacing the first order at their expense.

Australia Post says senders are entitled to compensation when parcels go missing.

Ms Kernaghan is one of many Australians experiencing major delays on parcels who have taken to Facebook to complain about overdue or lost parcels.

"I think every single other business at this time has adapted and sorted out a way to get through coronavirus and everything that's going on at the moment," she said.

"And at the moment, we're not really seeing anything from Australia Post or hearing anything. It's just, 'Sorry, coronavirus' — that's it."

Australia Post declined to comment specifically on Ms Kernaghan's case.

Posties retrained to cope with demand

Australia Post is making parcel deliveries its priority. ( ABC News )

Australia Post has since announced it would overhaul its service to focus on parcels over letters, reducing letter deliveries in metropolitan areas to just once every two days.

It will also retrain 2,000 motorbike posties to deliver and process parcels to combat the unprecedented demand during the coronavirus crisis.

"It's like a whole new army that can be appointed to delivering parcels," Ms Holgate said.

"So it should enable packages to be delivered much faster, particularly for regional places where it's really critically important because nobody else goes there."

Ms Holgate says the changes in air freight have made it especially difficult to service regional areas, but believes nine out of 10 of parcels should be getting through on time.

"We are doing everything we can to get resources through."