Environmentalists have selected this coming Sunday as a "Save Our Koalas day of action", and Wollongong historian Michael Organ said this area was "very much the home of the koala".

Mr Organ, a former Greens Federal MP, said a koala was spotted on May 24 in Georgina Ave, Keiraville.

"It stared into some car lights and calmly crossed the road into another yard before disappearing," he said.

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Koala scratchings were found on trees near the University of Wollongong recently, a koala cry was heard in bush at Thirroul in January, and a koala was captured on film at Mt Kembla in 2016.

"Koalas are Indigenous to the Illawarra and have been so for thousands of years," Mr Organ said.

"They feature in local Aboriginal storytelling. The first live specimens scientifically studied in 1803 came from Mt Kembla. As such, Wollongong is very much the home of the koala."

Mr Organ said the escarpment and adjacent conservation areas could be ideal protected areas for koalas, and a submission had been sent to Wollongong City Council in July urging it to act.