From September 28, the wage subsidy will be slashed from $1500 per fortnight to $1200 for full-time workers, and $750 per fortnight for part-time workers.

The rate will be further reduced to $1000 per fortnight for full-timers and $650 for part-timers from January.

Businesses will also have to comply with a new turnover test.

Based on Treasury data on the number of businesses receiving JobKeeper in June, Labor estimates the changes will impact nearly 38,000 workers and around 10,000 businesses across the ACT.

This will amount to a $33 million hit per fortnight, Labor says.

Fenner MP Dr Andrew Leigh said the second-order effects of losing that money would be massive.

"We're talking about more than $15 million per week ripped out of the ACT economy," Dr Leigh said.

Canberra MP Alicia Payne said it was the wrong time to wind back JobKeeper.

"You only have to speak to a shop assistant, a barista or a small business owner in Civic to know that they are on JobKeeper and it is the only thing keeping food on their tables and businesses from going under," Ms Payne said.

Member for Bean David Smith called on the government to keep JobKeeper at the full rate.

"Just last week I meet with a local tour operator and they said that 'as soon as JobKeeper is cut, we will have to reduce staff hours'," Mr Smith said.

"These are local families and local workers that are affected."

Canberra Business Chamber chief executive Graham Catt said he was expecting many businesses would not qualify for JobKeeper 2.0.

It would be a struggle for these businesses to survive, even if they did not meet the criteria, Mr Catt said.

"A business operating with a 75 per cent of their income and 90 to 100 per cent of their fixed costs will still be struggling, and after more than nine months of it doing tough many of our most affected businesses will have no choice but to cease trading," Mr Catt said.

"It is difficult to quantify just how many businesses may close but in some sectors we are hearing that this could be as many as 20 per cent of businesses currently operating."

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This would have flow-on effects for the whole ACT economy, Mr Catt said.

"Those in hospitality and retail who deal directly with customers will feel the impacts of business closure, job losses and redundancies as people tighten their belts and cut back on discretionary spending while others still in employment dial down their risk and save rather than spend," he said.

"This will have a significant impact on the whole ACT economy, and most directly on the private sector. It is absolutely critical that we are doing everything we can to support businesses, create jobs and help the economy recover."

It comes as the Morrison government encourages people whose JobKeeper payments are reduced next week to apply for unemployment benefits.

Workers on the $1200 per fortnight payment may be eligible for a partial JobSeeker payment, lifting their total income to $1476.

People receiving JobKeeper at the part-time rate of $750 per fortnight could receive another $546 in unemployment benefits, boosting their incomes to $1295.

"We have temporarily put arrangements in place so that our social security safety net is not just for people who have lost their jobs," Social Services Minister Anne Ruston said on Monday.