The multi-year battle over the ugg trademark began in 2016, when Deckers sued Mr Oygur and his company for selling a dozen ugg boots into the US.

In 2019, a Chicago jury found Mr Oygur and Australian Leather had infringed Deckers' trademark.

Mr Oygur said he was facing the collapse of his business, owing $US450,000 ($572,629) in damages and millions in legal fees.

His lawyers, including former senator Nick Xenophon, were hopeful following last week's hearing in the US Court of Appeals for the Federal Circuit in Washington DC.

However, today they said they were "gobsmacked" after the appeal was rejected with no reasons given.

"I have no choice but to take this all the way to the US Supreme Court," Mr Oygur said, calling for government support for his fight.

"It has cost thousands of Australian jobs because ugg boots should be made here rather than overseas, which is where Deckers makes them."

While Deckers has pursued Mr Oygur over the sale of products labelled "ugg" into the US, Mr Oygur's legal arguments have centred on the legitimacy of the ugg trademark itself.

The term is widely used in Australia to refer to sheepskin boots, but in major markets, including the US and the UK, Deckers owns the UGG trademark.

The appeal court heard Australia Leather's argument that a rule of US trademark law — the doctrine of foreign equivalents — meant Deckers should not have been able to trademark "Ugg" in the US decades earlier.

Deckers argued the doctrine was not relevant because Americans did not recognise "ugg" as a descriptive term, only a brand name.

You know where to stick your 'Deckers' now!