Treasurer Jim Chalmers says he’s “pretty relaxed” about the accidental release of advice warning the government is not going to meet its housing target and urging to raise taxes.

Independent Treasury advice unintentionally sent to the ABC reportedly contains subheadings that said the federal government’s promise to build 1.2 million homes by 2029 “will not be met” and calls for “additional revenue and spending reductions” to achieve a sustainable budget.

Though he acknowledged Treasury’s advice had been sent “in error”, Chalmers said such incidents happened occasionally.

“I’m pretty relaxed about it, to be honest,” he said in Canberra on Monday.

“Treasury advises governments of both political persuasions – that advice can’t be always adequately captured in the subheadings.”

In May, a report from the National Housing Supply and Affordability Council – another independent government advice body – warned the Albanese government would fall short of its goal by about 300,000 dwellings.

It followed a report in March commissioned by the Property Council of Australia showing the government needed to build another 462,000 homes to meet its 2029 target.

Asked about regrets in setting a housing target, Chalmers said the federal government needed to be ambitious.

“We’d rather have a big, ambitious, difficult target and work around the clock to meet it … than to continue the approach of our predecessors, which was to build too few homes,” he said.

“We’re investing tens of billions of dollars. We’re working well with the states and territories and local governments. We’re engaging with the industry. We’re trying to get the capital flowing. I’ve changed the tax arrangements for build to rent.

“But we’ll need to do better, and we’ll need to do more, and the advice just reflects that.”

The government has also attempted to improve its bottom line by reining in spending on the National Disability Insurance Scheme and proposing an increased tax on super balances above $3 million.

Chalmers has pledged to strengthen Australia’s economy ahead of a trip to South Africa, where he will meet his counterparts from other G20 countries as they deal with “extreme global economic uncertainty”.

Economic ties with countries such as Indonesia, Japan, Britain and Germany could be strengthened as leaders discuss capital flows, supply chains, critical minerals and issues within their own communities.

But domestically, one of the key focuses of Labor’s second-term economic agenda will be to boost productivity.

Meanwhile, the agenda of an economic reform roundtable, to be held in August, has been finalised. Reserve Bank governor Michele Bullock will kick off day one, Productivity Commission chair Danielle Wood will lead day two and Treasury secretary Jenny Wilkinson will head day three.

Opposition Leader Sussan Ley claimed the government was “ignoring some of the very levers that matter most” in the productivity puzzle.

While Chalmers acknowledged he could not invite every industry, he said there would be many opportunities for people to contribute.

-with AAP