Their comments come in the wake of a major tightening of the Greater Sydney lockdown, as NSW recorded 111 locally-acquired cases on Saturday, 29 of them in the community while infectious.

Premier Gladys Berejiklian announced that as of 11.59pm, non-essential retail would close and all construction would pause until July 30.

Workers and businesses in Sydney's southwest are even more heavily restricted, as residents in three local government areas are forbidden from leaving their council boundaries.

Business NSW chief executive Daniel Hunter supports the need for a tougher health response but says the economic fallout will be immense.

"There's no sugar coating that it will have a huge impact on all businesses right across NSW," he told AAP.

The shutdown of the construction sector alone will mean a loss of $800 million to $1 billion per week.

There is good financial support available but it will not cover all losses and some businesses will not survive, Mr Hunter said.

He highlighted the national economic impact of the Sydney shutdown, saying the region accounted for about a third of Australia's GDP.

Unions NSW secretary Mark Morey called for the revival of JobKeeper to give workers and employers "certainty and security rather than ambiguity and confusion".

"Jobkeeper is the answer. It provides all affected workers with a liveable income of $1500 per fortnight while maintaining the connection to their employer," he said in a statement.

"The ever changing criteria and levels of support payment from the Commonwealth and NSW governments are confusing and bewildering."

NSW and the federal government unveiled financial support for workers and businesses on Tuesday.

The state expanded its business grants and either cut or deferred payroll taxes for most companies.

Workers who have lost eight or more hours a week as a result of the lockdown will be able to apply for federal support through Services Australia for up to $600 per week.

On Saturday, Ms Berejiklian said businesses did not need to stress about cashflow problems.

"Over and above what the federal government has given, we are giving billions and billions extra. Everyone is able to get those payments if you are an individual or you can't go to work anymore," she said.

"Even if it takes a few weeks for businesses to get that money come through the door, at least when they are dealing with financial institutions and others, those institutions can be rest assured that that money is coming through the door."

Businesses can go to Services Australia at servicesaustralia.gov.au to apply for support or Service NSW at service.nsw.gov.au for assistance.

Australian Associated Press