The demonstrations, which included chants, speeches and placards, coincided with protests around the world on Global Day of Climate Action on Friday.

In the latest round of action, organisers Illawarra Climate Justice Alliance gathered with concerned residents at the arts precinct in Burrelli Street from 4.30pm.

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Protesters had many other demands including no new coal, gas or oil development in Australia, a rapid transition to renewable energy, and an end to Adani's Carmichael coal mine.

Rally co-chair Darcy Turner said "WaterNSW said the proposed expansion of the Dendrobium mine would drain 3.3 billion litres a year from the catchment, meanwhile swathes of Australia is in drought or on fire. This is unacceptable."

Medical doctor Rada Germanos spoke on behalf of Protect Our Water Alliance, a group which has been campaigning against the expansion of mining in the catchment, after protesters marched up Burelli Street and occupied the intersection of Kembla and Crown streets.

"Any expansion will create further permanent damage to the land and water courses, and will have a hugely detrimental effect on the whole ecosystem," she said.

"As the impacts of the climate crisis grow, water supply will become increasingly important."

The rally finished with a dance to disco tune 'Staying Alive'.

Alliance high school representative and rally co-chair Lola Kyra said the group was determined to keep calling demonstrations until action was taken to address the "climate crisis".

"It's important for everyone to join in," she said.

"The longer we wait around for governments and industry to do something the harder it will be to reverse the devastating effects we are already seeing."

Police approved the rally, blocked off streets and were out in force.

Meanwhile a small group of people gathered to protest outside Cunningham MP Sharon Bird's office on Friday morning to encourage her to oppose the Adani coal mine.