ACT businesses doing it tough and now grappling with the extension of Canberra's Covid lockdown until at least October 15 will be offered extended and expanded "top up" financial support.

As well, extra support is on the way for local businesses, such as tourism, hospitality and the arts, which have had the 'double blow' of the ACT lockdown, as well as the effects from lockdowns in other parts of the nation.

They can now access a COVID-19 Tourism, Accommodation Provider, Arts and Events and Hospitality Grant worth up to $20,000.

ACT Liberal Senator Zed Seselja said it was important to assist local business as they dealt with the extension of the local lockdown.

"It was a real blow and particularly to those businesses who can't operate at all," he told The Canberra Times.

"[There are] some businesses that are operating, but obviously still at pretty significantly reduced turnover because of the lockdown.

"And then there are others that are simply barred from operating and all of those businesses are doing it tough.

"We now have businesses, medium-sized businesses that are losing a significant amount of money every week, tens of thousands or even hundreds of thousands of dollars in turnover every week."

The 50-50 split, joint ACT and Commonwealth funded COVID-19 Business Support Grants has been extended for another fortnight to October 1, when it will be further assessed.

"We're increasing the support, we've got a team of more than 100 assessors working seven days a week to make payments," ACT Chief Minister Andrew Barr said on Wednesday.

"There's about $18 million that have been paid out already.

"Once again, I thank Treasurer [Josh] Frydenberg and his office for their detailed engagement with the [ACT] government."

The ongoing package of COVID-19 Business Support Grants provides one-off payments of up to $20,000 for employing businesses and $7500 for non-employing businesses which have experienced a 30 per cent decline in turnover because of the lockdown.

A tiered additional payment will now be available for businesses of varying sizes.

For businesses with a turnover greater than $2 million and less than $5 million there is a $10,000 payment.

There is $20,000 for businesses with a turnover greater than $5 million and less than $10 million. Businesses with a turnover greater than $10 million can apply for a $30,000 one-off payment.

Businesses already in the system will not have to reapply and will be automatically granted the payments.

There is also a new COVID-19 Tourism, Accommodation Provider, Arts and Events and Hospitality Grant.

Non-employing businesses can receive $1000. There is $3000 for employing business with a turnover less than $2 million.

There is $10,000 for employing businesses with a turnover between $2 million and $5 million. And $20,00 for employing businesses with a turnover greater than $5 million.