Andrea Schutz, who was born in Austria, said that 1,200 customers of the Cardinal's Hat had signed a petition backing her stand.
Schutz said: "They can fine me if they want to, but we will continue serving our beer in steins and flutes.
"It is what our customers want. Some of them have said they will rent or buy a stein and ask me to fill them up if they have to.
"How can it be that an Irish pub in Austria can serve its drinks in pints without being prosecuted? It's a crazy situation."
Schutz has the backing of the Metric Martyrs, the pressure group which defends traders' rights to sell goods in all traditional measures.
Neil Herron, the organisation's campaign director, said: "This case with Andrea highlights the total absurdity and hypocrisy of the metric regulations. This has to go back to central government for ministers to sort out because it is a total and utter nonsense."
The organisation has promised to pay any fine and legal costs which Schutz may incur.