Record-breaking temperatures and drought conditions have fuelled dozens of huge bushfires across the country in recent weeks, claiming the lives of 28 people and an estimated half a billion animals.
The charity said in a statement that a fundraising page it started last week had been set up to provide funds for activities including restoring homes for wildlife and supporting the response and recovery teams.
The funds raised include "significant" donations from the footballers Hector Bellerin and Aaron Ramsey and the Formula 1 driver Lewis Hamilton, the charity said.
Michael Dent, executive director of supporter income and engagement at WWF-UK, said: "This is an incredible response from the UK public and we are beyond grateful for the ongoing support.
"The £1m raised so far will have a significant impact in providing emergency funds to care and restore homes for wildlife, support response and recovery teams and to pressure governments to strengthen laws that prevent excessive tree clearing.
"We’ve been left shocked by the devastation to Australia and need to continue in the fight to protect our world against the climate crisis."