Blinky the Koala, a four-metre tall, smoke-breathing robot was part of the procession, which saw protesters gather under a red, teal and green banner.

Labor's 43 per cent emissions reduction target is expected to be introduced to the House of Representatives on Wednesday and voted on over the next two sitting weeks, before the vote reaches the Senate in September.

Extinction Rebellion spokesperson Jane Morton said the group wasn't taking a position on whether the 2030 target showed enough ambition, as the first step should be to declare a climate and ecological emergency.

"43 per cent ... 75 per cent ... it's not the important thing," she said.

"The important thing is acknowledging that it's an emergency and then making it your absolute first priority across all departments of government."

The ACT joined many other cities, states and territories around the world to declare a state of climate emergency in May, 2019, followed by South Australia earlier this year.

Greens leader Adam Bandt's attempt to have a climate emergency bill introduced to parliament in 2019 was voted down by the Liberal government.

The bill, which had the support of the Labor opposition at the time, was labeled a "grand symbolic gesture" by the Morrison government.

Ms Morton said while a declaration doesn't promise immediate action from those in power, it provides a platform to start campaigning for emergency action.

"It's a line in the sand, once the government acknowledges there is an emergency," she said.

Labor will need the support of the Greens to pass its emissions-reduction target, with future investment in coal and gas projects expected to be a sticking point.

Prime Minister Anthony Albanese reaffirmed on Tuesday he does not support a blanket ban on all new coal and gas projects.

"That's not the policy of the Labor Party and we won't be supporting it, because that would have a devastating impact on our economy," Mr Albanese told ABC's 7.30.

Liberal party member Bridget Archer has signaled she is willing to cross the floor to support the bill, as part of her bid to help end the climate wars.

Climate Change Minister Chris Bowen said on Wednesday while there are some Liberals who get it, the party still lagged behind on climate action.

"This is the modern Liberal party, unfortunately for Australia, this once-great party. It's changed from Morrison to Dutton. But really, nothing has changed," Mr Bowen told ABC radio.

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"They don't get action on climate. They don't think Australia needs action on climate. They don't see the jobs opportunity from action on climate. They don't see the investment opportunity. They haven't gotten the memo. They haven't changed. It's the same old Liberal Party."

Extinction Rebellion were expected to take Blinky across Commonwealth Bridge to Civic at around mid morning.

Ms Morton said Blinky is representing the billions of animals killed in the 2019-20 climate fuelled bushfires and all those at threat of extinction.

"Extinction Rebellion calls on the government to act now to reach net-zero emissions at emergency speed and halt biodiversity loss.

"UN Secretary General Guterres warned recently that humanity is is in a climate crisis facing 'collective action or collective suicide'.

"Australia is one of the largest exporters of coal and gas in the world. We are a huge part of the problem.

"There is no way that any new coal or gas projects 'stack up environmentally'."