There are many impacts of the coronavirus/Covid19 pandemic on workplaces in Australia, and there has been a significant number of stand downs of employees by large companies such as Qantas, Virgin Australia, Myer and so forth. I have published several posts about the legality of this in recent days.
There has also been a significant trend amongst particularly small businesses to ask staff to enter into amended contracts of employment. Contracts of employment are bilateral in the sense that they cannot be amended unilaterally by an employer and without the consent of the employee unless they contain a clause to that effect, which is quite rare.
Small businesses* which are companies and are subject to the Fair Work Act are not required to pay redundancy pay. Consequently, small businesses have considerable clout when demanding of employees that they enter into amended contracts. Employees who refuse have little practical bargaining power to push back. Nevertheless it is unlawful for an employer covered by the Fair Work Act to take adverse action against an employee in part because the employee exercises a workplace right to refuse a unilateral amendment to a contract of employment.
Lesson; this is a tricky legal environment and taking employment legal advice is very wise.