Immigration Dob-in Line
Telephone: 1800 009 623
Use this number to advise the department about a person working or living illegally in Australia
Hours of operation
8.30 am to 4.30 pm Monday to Friday (voicemail facility available out of these hours)
Fax Number
1800 009 849
Alternatively, you can fax information to the department.
See: Immigration Dob-In Line
I've made my call. It costs about a dollar from a mobile , FREE from landline.