While the pandemic has shut the gate on people attending farm clearing sales they have been going gangbusters online.

Auction houses are reporting red-hot buying activity for their online clearing sales with bidders logging in from all over the country.

The COVID-19 shutdown of buyers physically attending farm clearing sales and machinery auctions has coincided with big autumn cropping rains in many regions and a hefty lift in instant tax write-offs on new and used machinery purchases to stimulate spending.

Coronavirus has also delayed the delivery of new farm machinery from Europe and the United States at a time when many farmers are seeking to re-equip after the drought.

Rural online trading site, AuctionsPlus, has seen monthly online clearing sale listings jump from two to three to between 10 and 20.

Matt Cotton who heads machinery operations for AuctionsPlus said bidding during online clearing sales had been much stronger than expected.

"The majority of vendors and agents I have spoken to said they obtained higher prices than they were expecting if they held a live auction," he said.

"I think we will see a number of repeat customers going off the strength of the results."

Clearances at recent AuctionsPlus sales have been running at around 80 to 100 per cent.

Buyer logins topped at 3517 for the Marke Pastoral Company clearing sale near Tatura, Victoria, in May while the top price was $193,000 for a Komatsu D155 AX-5 dozer at the Lagoona clearing sale at St George, Queensland, in April.

"I am a fan of the live auction, however going online is certainly the future and taps into a much wider audience," Mr Cotton said.

Chris Goscomb from the Ray White Nasco auction house, agreed saying many people were now more computer savvy and a farmer could bid on an item via a smartphone sitting in a tractor cab.

The company has been running a national monthly online farm clearing sale and Mr Goscomb said prices had been strong.

"Every man and his dog is trying to burn diesel at the moment," he said.

Meanwhile, big auction house, Manheim, is now having trouble getting enough listings to meet demand for its online sales of farm equipment.

Manheim's national head of agriculture in Australia, Bryan McNeilly, said the Federal Government's lift in the instant asset write-off threshold from $30,000 to $150,000 along with a good season was driving strong demand for used farm machinery.

Buying activity had lifted 25 to 30 per cent and there was now a shortage of listings.

Farm tractors had been the focus of buying activity but he expected attention would shift to headers as the grain harvest loomed.

He said many farmers couldn't afford to pay the price for new machinery.

Manheim mainly handles listings from dealers and big corporates.