It doesn't appear you're working off the current version of the REIQ Commercial Tenancy Agreement, but I don't think the outcome is any different. The below clause references are to the current version, so just check to make sure they haven't changed that part.
Unless you have a special condition to the lease which changes things Standard Condition 2.3 provides if you continue to occupy the premises with consent after the end of the term, it's on a monthly tenancy. You need to give one month's written notice "expiring on any day" to terminate. This means you give at least one month's notice, it doesn't have to be exactly one month.
This situation is different to the Property Law Act default position for continuing monthly tenancies. This does not apply under the Commercial Tenancy because of the above Standard Condition, unless there is a special condition in effect - I mention it for information and context.
Under the Act you need to give notice which equates to the balance of the current month you are in plus the next month (i.e. between 1 - 2 months). In practical terms under the Act: Say your monthly term started on the 15th of the month. If you decide to terminate on 22 March, 2018, you would give notice to terminate to have effect on 14 May, 2018. That is, the balance of the 15/3 to 14/4 period, plus the 15/4 to 14/5 period.
The reason I mention this is neither of the above means you need to give a three month notice period. Again, however (and this is important) - check you agreement's special conditions.