"I stopped on my bike and he walked right up to me, quite quickly for a koala, and as I was giving him a drink from all our water bottles, he actually climbed up onto my bike.
"None of us have ever seen anything like it."
It was 40C in Adelaide when the koala approached the cyclists and heatwave conditions are again developing over South Australia, peaking on Monday.
Country Fire Service crews will be placed strategically around the Adelaide Hills fire ground as weather conditions deteriorate over the next three days, with authorities warning that any outbreaks will be difficult to suppress.
The CFS is particularly concerned about weather forecasts for Monday when temperatures are likely to hit 40C in Adelaide, with strong winds, ahead of a cool change.
Sky News Meteorologist Rob Sharpe said the heatwave was currently moving through southern parts of Australia.
"Initially, winds are not going to be that strong so we're going to see a few regions with severe fire danger on Saturday and Sunday.
"It's not going to be that dangerous, but it really ramps up at the end of heatwave on Monday."
He said that on Monday, strong winds will "suddenly" pick up and severe heat will hit Victoria, South Australia, NSW and even Tasmania.
Devastating bushfires this season have resulted in the loss of at least 2000 koalas on the state's north coast, a parliamentary inquiry heard earlier this month.
The animals died either in bushfires or from starvation and dehydration afterwards, North East Forest Alliance president and ecologist Dailan Pugh said.
The Total Environment Centre said the government's policy is effectively toothless unless councils are made to urgently complete a koala management plan.
"Survival of koalas is at emergency level with the decline of populations, loss of habitat and the bushfires," centre director Jeff Angel said. "We urge the government to do more, and quickly."
The centre has called on the government to set aside $2 million to support the plans.
The Nature Conservation Council also called for councils to be obliged to produce a plan.
"If the NSW government is serious about koala conservation, it should make the development of koala plans of management compulsory for all identified regions and ensure all councils have the resources they need to implement them," council campaigner Shirley Hall said.