With a new regulation passed, the Australian authorities have become very strict in granting PR. Any false information in the visa application will lead to the applicant being debarred for a period of 10 years. Hence, it is best to state truthful information and this is the reason Australian authorities verify employment record.
It is not necessary that they will report physically to the office or do phone calls, unless and until they are suspicious about your documents or they find something dubious.
Hence, it is very important to have all your documents double check and no adulteration should be done.
Generally, they do a thorough check of all your documents submitted and special emphasis is done on written documentation produced, such as pay slips, reference letters, tax return documents, and bank statements. Immigration authorities might contact your previous organization employers.
DIBP works directly with independent bodies/agents/consultants who do the reference checks, background information and other formalities on their behalf.
Therefore to avoid any cancellation of your Australia skilled Immigration (190) PR Visa, it is best advised to get an opinion from a registered MARA visa immigration consultancy.