SANTIAGO (Reuters) - Chile’s Supreme Court has upheld a ruling that declared it illegal to dismiss workers for striking outside of a formal collective bargaining process, a decision that could have ramifications for future labor disputes.

The ruling is potentially significant for mining companies in the world’s top copper exporter, which in the past have dismissed and replaced workers after unauthorized strikes without legal repercussions.

It comes at a time when businesses are already girding for increased costs due to a wide-sweeping labor reform making its way through Congress, set to give unions more power.

In the decision late Monday, the Supreme Court affirmed the judgment of a lower appellate bench that had overturned the dismissal of two call center workers after they led their colleagues in a walk-off.

“If striking is a fundamental right, then the business measures that limit it, like replacing striking workers...must be seen as schemes that should be eliminated,” the appeals court said in its original October ruling.

One of the most hotly debated aspects of the upcoming labor reform legislation is a provision that would make replacing striking workers more difficult. The bill is opposed by business leaders and the right-wing opposition, and centrist members of the governing coalition have balked at key aspects, repeatedly delaying its passage.

Multiple sections of the bill are expected to face a legal challenge from a tribunal that rules on the constitutionality of pending legislation, lawyers say.