It is understood that an additional request of about 20 is being prepared.
The fires stretching across New South Wales and Queensland have killed three people and destroyed at least 150 homes.
According to the Australian news website news.com.au a combination of air temperature, winds and dry conditions could create severe dangers.
"Areas such as the Hunter, the Illawarra and greater Sydney are all under 'catastrophic' fire danger warnings – the first time Sydney has ever faced that kind of threat since the new rating system was implemented 10 years ago," the website says.
A total of 64 fires are burning and 40 of them are not contained.
Premier Gladys Berejiklian declared a state of emergency in New South Wales today.