GDANSK, Poland, Feb 2 (Reuters) - Poland's consumer regulator UOKiK said on Monday it had fined telecoms operator Orange Polska more than 34 million zlotys ($9.6 million) for illegally charging customers for inactivity.

UOKiK said the company unilaterally changed contract terms to introduce a fee for "maintaining the number in the network" for customers who had not made a call, sent a text or used the internet in the last 30 days. 

The fees were charged between May 2022 and January 2024.

"Changing contract terms is illegal without an appropriate modification clause," UOKiK President Tomasz Chróstny said in a statement. "Consumers cannot be surprised by additional fees and operator-imposed requirements."

The decision is not final and the company can appeal it in court, the regulator said. 

Orange Polska told Reuters it had received the decision, provided UOKiK explanations on the matter and informed it about actions taken. It did not say whether it planned to appeal the decision.

($1 = 3.5573 zlotys)

(Reporting by Alicja Surdy, editing by Milla Nissi-Prussak)