Do sole traders & companies need to be registered for GST to apply for a credit limit?

If the business GST turnover (gross income minus GST) is $75,000 or more then yes, the sole trader or company will need to be registered for GST.

It is the responsibility of the sole trader or company to register for this, failing to do so might mean you need to pay GST on sales you’ve made since the date you were required to register as well as other penalties and interest. You can visit the Australian Taxation Office for more information on how to register.

If your GST turnover is less than $75,000 then registering for GST is optional, if you’re a non-profit organisation your threshold for GST turnover is slightly higher at $150,000 or more