Fitch Ratings has upgraded Australia's credit rating outlook to stable, from negative, indicating its top-tier triple-A rating is safe for the foreseeable future.

Treasurer Josh Frydenberg said this was a "clear expression of confidence" in the Morrison government's economic management.

The global credit rating agency said the upward revision reflects its confidence in Australia's fiscal consolidation path and stabilisation of debt over the medium term.

"(This is) supported by the underlying strength of the economic recovery, despite a near-term setback from recent pandemic-related lockdowns," Fitch said in a statement.

"We expect Australia's economic recovery to continue."

Fitch said a wave of COVID-19 cases that began in June, against a sluggish start to the country's vaccination campaign, led to lockdowns in the two largest states in NSW and Victoria, which account for over half of national output.

"The pace of vaccination has accelerated in recent months, allowing a gradual easing of restrictions that will facilitate a strong rebound in consumption from pent-up demand, particularly households which have large accumulated savings to draw down, and have had access to targeted fiscal support during the lockdowns," Fitch said.

While Fitch has lowered its economic growth forecast for Australia to 3.7 per cent from 5.8 per cent for 2021, it expects the economy to expand by 4.5 per cent in 2022 compared to a median of 3.6 per cent among other triple-A rated countries.

Mr Frydenberg said emerging from a once in a century pandemic and the greatest economic shock since the great depression, Australia remains one of only nine countries to maintain such a rating from all three major credit rating agencies.

Standard & Poor's and Moody's Investors Service also rate Australia at triple-A.

"The Morrison government's economic recovery plan is working, but the job is not done yet," Mr Frydenberg said in a statement.

"We must stick to the national plan agreed to at national cabinet to open up safely and secure our economic recovery."