This blog is one of a series about defences to infringing another person’s intellectual property.  I have already blogged about cease and desist letters – here – and descriptive defences to trade mark infringement  – here.

First to use defence

A trade mark dispute typically starts with a “cease and desist letter” (also called a letter of demand) – see my blog here.  If you receive a letter that claims that your business is infringing someone else’s trade mark registration, one thing to consider is whether your business (including any predecessor in business) has used the trade mark first.  Typically (although not always), in a conflict between a registered mark and an unregistered mark, the first to use their mark in Australia wins.

There are 2 important dates in this defence to trade mark infringement:

1. the registration’s “Registered from date” – which you can see on the Trade Marks Register – https://search.ipaustralia.gov.au/trademarks/search/quick – this is often (but not always) the same as the filing date of the application; and

2. the date of first use of the registered mark by the trade mark owner or their predecessor in business – which you are unlikely to know.

You will need to be able to prove that you have “continuously used” your mark (which means without substantial breaks) before both of these dates.  This defence may not be available if you used several similar but different marks over the period. 

You can try to find out if the trade mark owner has been using longer than you by, for example, using the Wayback Machine to search old versions of their website: https://web.archive.org/.

Honest concurrent use defence

Even if you were not the first to use the mark, there is another defence to infringement if you can prove that you were an “honest concurrent user” – which means that you honestly adopted your mark and have made substantial use it at the same time and in the same area as the registered owner, so that you would have been entitled to register your trade mark. 

This is quite a complex defence that would consider a hypothetical application for your unregistered mark and any potential grounds of rejection of the hypothetical application.  This needs the expert advice of an experienced trade marks lawyer.

I have acted in many trade mark infringement matters, both sending cease and desist letters on behalf of clients and advising clients who have received them.  I can help both trade mark owners and recipients of cease and desist letters.

This blog provides general information only, and is not intended as legal advice specific to your circumstances.  Please seek the advice of a lawyer if you have any particular questions.

Liability limited by a scheme approved under Professional Standards Legislation

© Margaret Ryan, Melbourne, Australia, 2026