Josh Frydenberg has put lower company tax rates and industrial relations reforms back on the table as a way to boost growth, prompting Labor warnings the Coalition will use the Covid-19 crisis to “dust off its ideological obsessions”.

As Australia’s health results improve and national cabinet signals Covid-19 restrictions could be eased as early as May, the Morrison government has called for pro-growth policies, prompting business demands for industrial relations deregulation.

On Tuesday the Reserve Bank governor, Philip Lowe, confirmed Australia’s economy is expected to suffer its biggest contraction since the Great Depression, and the treasurer met with the largest employer groups to discuss ways to boost investment.

Lowe sketched out a scenario in which Australia could grow by 6% to 7% in 2021 in a V-shaped recovery of the same size as the downturn, calling on governments to pursue reform including changes to the tax mix, pricing of infrastructure and “the flexibility and complexity of our industrial relations system”.

On Wednesday, Frydenberg said that Lowe was “absolutely right that Australia must continue to embrace the productivity agenda”.

He nominated the government’s union penalty bill as the “first order of business to get through the parliament”, claiming the bill to make it easier to disqualify union officials will lower construction prices.

Frydenberg told Radio National that Australia’s company tax rate of 30% is “uncompetitively high”, explaining the Coalition “did what we could, which was to reduce the rate for small and medium businesses”.

“We tried to do it, but unsuccessfully, for larger-sized businesses.”

Frydenberg said the government had “no plans” to increase the goods and services tax, but did not rule it out.

The Labor leader, Anthony Albanese, said the government had indicated it will return to “the old rightwing agenda … out of the bottom drawer” after the crisis is over.

Albanese said the proposals amounted to “further attacks on unions” and the wages and conditions of working people “who are, after all, seeing us through this crisis”.

Albanese argued a company tax cut would decrease revenue rather than help pay down debt, but did not rule out support for it.

Earlier, the shadow treasurer, Jim Chalmers, accused the government of using coronavirus as an “excuse to dust off its ideological obsessions”, citing early access to superannuation and regulations to ease employers changing workplace agreements to cut pay and conditions as examples.

Chalmers said that he was concerned the RBA estimated hours worked will fall by 20% because under-utilisation of workers will worsen already stagnant wages.

“We want jobs to be central to the recovery,” he told an Australia at Home briefing.

“We have made it very clear that the highest priority is job creation – we can’t go on as we have … for seven years, relying so heavily on insecure work, we can’t go on relying on an IR system that has delivered consistently stagnant wages.

“Because if we want to get demand going, people have to have spending power and they haven’t had that for a long time now.”

Chalmers argued Australia should encourage broad-based growth by investing in renewable energy to lower power bills, public housing, innovation and domestic manufacturing.

The Greens leader, Adam Bandt, seized on the RBA’s tax reform call, proposing an end to “unjustifiable tax breaks to the big polluters and instead offering incentives to research, development and innovation”.

The Australian Industry Group has called on the government to reverse the trend of fewer employers negotiating workplace pay deals, to provide a definition of casual employees to avoid “uncertainty” and to make “major changes” to simplify modern awards that set employees’ pay and conditions.

The Ai Group chief executive, Innes Willox, said “to successfully navigate out of the current crisis, increased workplace flexibility is essential”.

“The Covid-19 crisis necessitates an approach to IR reform that does not just tinker around the edges,” he said.

Willox said the system could be “more productive and flexible … without compromising fairness for all parties”.