Rollover and exemptions for capital gain only be available in some special circumstances such as:

    - Destruction or compulsory acquisition of property.

    - Marriage or relationship breakdown.

    - Transfer asset or the capital proceeds from the sale of an asset into a superannuation fund to satisfy certain conditions under the small business retirement exemption.  

Client only can defer the CGT once in a lifetime.

Client may be able to rollover (defer or disregard) a capital gain or loss from capital gain tax if CGT event happens involve is the following scenarios:

All the above information is pointed out the frequent circumstances in real life. To read more in detail about all the circumstances  that your client may be able to defer capital gain, please refer to ATO website below:

See summary below for the Detailed consequences of choosing rollover