If you are not registered for GST, make sure to keep checking each month to see if you have reached the GST threshold or are likely to exceed it. You must register within 21 days of your GST turnover surpassing the relevant GST threshold limit. If you don’t apply for GST registration and are required to, you may need to pay GST on sales made since the date you were required to register. This could happen even if you didn’t include GST in the cost of those sales. You may also have to pay interest and penalties. To handle GST or other tax matters, you can seek help from the best accountant in Melbourne, who specialises in handling the tax affairs of a company.