Premier Steven Marshall says instead of closing off applications next month, eligible businesses will now have until the end of February to apply for a $10,000 payment.

"We know there are many businesses who continue to do it tough and we want to do everything in our power to assist," Mr Marshall said.

"The cash grants will be available to help cover ongoing or outstanding operating costs, such as rent, power bills, supplier and raw materials costs and other fees."

The government launched the second round of grants two weeks ago and has already received more than 4100 applications.

It has so far paid out grants to about 1200 businesses worth about $12 million.

In the first round of similar grants earlier this year it paid out $186 million to more than 18,700 companies.

Companies that received grants in the first round may also be eligible for another allocation in the second round.

The state government imposed new virus restrictions when the Parafield cluster of COVID-19 cases emerged in Adelaide's north last week.

They include limits on the number of patrons in pubs and restaurants and limits on the size of most gatherings, including weddings and funerals.

With the cluster now largely contained, South Australia is on track to ease those measures next week.

Australian Associated Press