A second highway designed to ease congestion between south Brisbane and the Gold Coast has been given final environmental approval, less than a week after a last ditch effort to review the project failed.

According to the project's environmental report, more than 246,000 vehicles are expected to travel along the existing M1 Pacific Motorway each day by 2041, with the Coomera Connector Stage One designed to reduce that by at least 16,000.

Queensland Transport and Main Roads Minister Mark Bailey said the Coomera Connector would take "upwards of 60,000 [vehicles] off the M1" when completed.

"You've got to look at the figure over time," he said.

The Coomera Connector was designed to provide an alternative north-south route along the fast-growing northern Gold Coast.

A last-minute request to reconsider the project due to what an environmental group called "substantial new information" about its environmental impact was rejected by the federal government last week.

Gold Coast transport woes

The Gold Coast's population has been tipped to grow from about 650,000 to one million by 2041.

The City of Gold Coast's transport strategy estimates each new resident adds 3.1 car trips per day to the road network, with each vehicle carrying one person on average during peak hours.

In 2013, the council estimated 3.1 per cent of resident trips were on public transport, increasing slightly to 3.3 per cent in 2021, which was well below the goal of 12 per cent by 2031.

Mr Bailey said the Coomera Connector, along with upgrades to the existing M1, were needed for "orderly growth".

"[Gold Coast is] one of the fastest growing regions in the whole country let alone the state," he said.

Mr Bailey said the project would not entrench car-dependency, with the state government also planning to add three new train stations at Pimpama, Hope Island and Worongary, along with a light rail extension.

"We're doing planning on heavy rail connection to Gold Coast Airport," he said.

"We're making public transport much more competitive.

"There's no way we can just keep building road and think it's going to work."

Environmental conditions welcomed

A federal Department of Environment spokesperson said 56 environmental conditions had been imposed on the project, including "establishing over 390 hectares of environmental offsets to restore and protect habitat for impacted threatened species and communities, including the koala".

Coomera Conservation Group spokesperson Karina Waterman said the approval "was not a surprise" and the conditions outlined "what measures [the state government] needed to do to ensure the longevity of those koala populations".

Those conditions include monitoring from an independent koala ecologist, and mandatory reporting of non-compliance with the project's environmental management plan.

"These things look good on paper but the reality may be quite different once the project proceeds," Ms Waterman said.

"If we do see certain things happen with those koala populations, that koala management plan needs to be looked at again and redone.

"Works would need to halt while that was happening."

Long-term issues remain

Ms Waterman, who also volunteers at a koala rescue service, said sprawling urban development presented a long-term threat.

"I see them on the roads, hit by cars," she said.

"I'm asking myself the question, 'How sustainable are our koala populations?'

"We're at a really pivotal point right now. This is the spot we have to draw the line."

She said the government had asked for "population viability analyses" at East Coomera and Coombabah "two years after the road was completed, which to me seems a little bit down the track".

"That's quite a way. By then the damage is already done."