The ECJ has started discussions on whether the new law which forces the retirement of Poland’s Supreme Court judges at the age of 65 breaches EU rules.
Poland’s Supreme Court has suspended the controversial law until the ECJ makes a decision.
But Mr Gowin has hit out at EU lawmakers, vowing to ignore the court’s ruling if it blocks the law.
In an interview with Polish weekly Do Rzeczy, Mr Gowin said if the ECJ backs Poland’s Supreme Court in scrapping the law the Polish government “will probably have no choice but to… ignore the ruling of the ECJ as contrary to the Treaty of Lisbon and the whole spirit of European integration”.
The Polish deputy prime minister said the the EU risks the rise of eurosceptic groups in Europe.
He said: “If the tribunal in Luxembourg considers itself competent to support a position of a small group of Polish judges, it will be fuel for eurosceptic communities across Europe.”
Mr Gowin said if the EU backs Polish judges over the government it would damage the principle of the sovereignty of individual countries in the bloc.
He said: “This will undermine the fundamental EU idea of the sovereignty of nation states.”
And Poland is pressing on with the reforms despite the possibility of EU opposition.
Last week the country nominated 12 new judges to replace judges removed under the new law.
The dispute is the latest disagreement between Poland and the EU over Polish judicial reforms, which Brussels say violate EU rules.
It comes at a time when the EU is under increasing pressure from various member states.
The UK is set to leave the EU in March next year.
And Italy has threatened to refuse to pay its contribution towards the EU’s budget over the ongoing migrant crisis.