Ammunition wholesalers in Australia are expecting one of the biggest supply shortages in recent history with American civilians purchasing arms at record speed.

Scrutiny of gun laws in the United States is thought to have sparked the gun sales boom, with the flow-on effects expected to reach Australian shores within weeks.

Some of the most popular bullets will soon be unavailable in Australia and New Zealand and will not be restocked for about another six months.

Firearm importers in Australia are being told to brace for supplies to run extremely thin or completely dry within weeks.

Importer Jade Cleaver says he has been buying more than usual in anticipation.

"We've been stockpiling ammunition in a sense so we don't run out," he said.

"Basically the American community is consuming the ammunition and the ammunition manufacturers can't keep up."

Australia's eight main firearm wholesalers source about 80 per cent of their stock from the United States.

Mr Cleaver says producers are operating around the clock in a bid to keep up with demand.

"There's only so much they can produce," he said.

"There's only 24 hours in a day and putting capital out for more machines.

"I know the products that we import into Australia; they've gone from running 12-hour shifts at their companies to running 24 hours."

Government departments run out of ammo supplies

Retailers say they have had state government departments in Australia asking for more ammunition after running out but are not allowed to name which ones.

A major recreational shooting club from the Gold Coast has been ordering four times its usual monthly quota.

Farmers in rural and regional Australia have been purchasing more ammunition as they grapple with a surge in pests on the land after recent heavy rain.

Firearm retailer David Auger says the shortage was expected and many retailers took it into account when submitting their last orders.

"[We took it into account] because we all knew there was a rush on sales in America, so obviously the suppliers can't keep up from the US," he said.

Recreational shooter Col Tanner says word about the shortages is spreading in sporting circles.

"I go to the gun club there and talk to them about different things and they say the same thing - they're finding it hard to get things," he said.

Earlier this year American media reported plans by Homeland Security to order more than 1 billion rounds of ammunition or about 20 years worth of bullets.

Those purchasing quotas are still being debated by the US House of Representatives.

Three of the five companies with major contracts to the Australian Defence Force have told the ABC they do not expect the civilian shortage to impact military arms sales.