The Northern Territory is the only Australian state or territory on track to close the life expectancy gap between Indigenous and non-Indigenous Australians within a generation – but it will still have the highest child mortality rate in the country.

The Indigenous Reform report, released on Wednesday by the COAG reform council, assesses Australia’s progress in “closing the gap”.

It says Indigenous Australians are still dying at twice the rate of non-Indigenous people.

Most states and territories had set a target date of 2031 – one generation – to close the wide gap in mortality rates, and, while the gap is narrowing for the report’s five-state total overall, the Northern Territory is the only place where current trends suggest they will make it.

In 2011 the gap between Indigenous and non-Indigenous Australians was 534.9 deaths per 100,000 people per year. In 1998 that number was 602.6. The aim is to reach zero by 2031.

By comparison, Northern Territory’s gap has dropped from 1,169 per 100,000 people in 1998 to 772.9 in 2011. It’s still high, but the trajectory has the Territory on the way to reach zero within a generation if it continues.

The council’s chairman, John Brumby, told Guardian Australia efforts are “clearly not being made at a rate that is fast enough”.

Brumby said changing the mortality gap was a long process, as life expectancy continued to increase for all Australians.

“The one point I'd make about life expectancy is that to fundamentally change life expectancy and reduce the gap won't and doesn't happen overnight,” Brumby said.

“These are huge improvements in life expectancy. So to close the gap, you need more than huge improvements in our Indigenous communities and at the moment we're not making those 'more than huge' improvements.”

Queensland’s mortality rate among the Indigenous population declined, but not enough to meet the target. The state needs to reduce the rate of Indigenous deaths by 40.7 per 100,000 every year. It has averaged 18.

Western Australia also saw a narrowing of the gap, but the state has not released a target or trajectory. The other states with data available – New South Wales and South Australia – showed no significant decrease since 1998, although the Indigenous death rates in those states are among the country’s lowest.

Circulatory disease, which includes heart attack and stroke, is the most common cause of death of Indigenous Australians. It was the leading cause of death in all states and territories except the Northern Territory, where cancer remained the biggest killer.

There was positivity in the report, with good progress made on three of the six targets set by the National Indigenous Reform Agreement (Close the Gap), made in 2009 and revised in 2011.

Australia is meeting targets to halve the gaps in child mortality rates and attainment of Year 12 educational qualifications or equivalent by 2018 and 2020 respectively. Early childhood education goals are also close to being met, prompting the government to set newer, more ambitious targets.

The Aboriginal and Torres Strait Islander social justice commissioner for the Australian Human Rights Commission, Mick Gooda, said these positive results were “building blocks” and showed that Australia had to “keep the effort going”.

“As a matter of fact,” he said, “I'd like to see an increase in effort because now's the chance. Once we start getting some of these trend lines heading in the right direction it’s a good base to build upon and make big changes.”

Nationally, the Indigenous child death rate fell by an average of 5.7 deaths per 100,000 per year between 1998 and 2011. But it remains double the rate of non-Indigenous children, and in the Northern Territory it is more than three times the national rate.

The report also reveals that 49.3% of Indigenous mothers smoked during pregnancy, compared with 12.5% of non-Indigenous mothers. This rate showed no significant change from 2007 results.

“Halving the infant mortality rate means we're doing a bunch of other things right: maternal and child health, ante-natal stuff,” said Gooda.

“If we can get pregnant mums to give up smokes all together, to give up alcohol, it’s going to feed these kind of results.”

There has been a larger effort in addressing the Northern Territory’s more extreme disparities in health among Indigenous people than in other states or territories.

There were a lot of resources that came in with the Intervention seven years ago, which is “the one thing I've always applauded” about the Intervention, said Gooda.

Gooda said the report showed how important it was that states and territories re-signed the National Partnership Agreement on closing the gap.

“We now need the states and territories to come on board, particularly those states that are lagging behind a bit in the health area,” he said.

The report looked at the Northern Territory, Queensland, New South Wales, the ACT, South Australia and Western Australia up to the year 2011, but data from all states did not always apply to each section.