ROME- An Italian court has annulled a fine of 228 million euros ($271 million) slapped on Italy's top four phone operators last year over a breach of competition rules for collectively agreeing to raise their prices.

Italy's competition watchdog had claimed Telecom Italia, Vodafone, CK Hutchison’s unit Wind Tre and Swisscom’s Fastweb had agreed to raise tariffs after being forced to scrap a billing scheme based on 28 days rather than a full month.

But a Rome-based administrative court said in a series of rulings published on Monday, and seen by Reuters, that the companies had been acting within their rights.

TIM declined to comment. The other companies were not immediately available for a comment.

($1 = 0.8422 euros)

(Reporting by Marco Carta, writing by Stephen Jewkes, editing by Giselda Vagnoni) ((stephen.jewkes@thomsonreuters.com; +39.0266129695; Reuters Messaging: stephen.jewkes.thomsonreuters.com@reuters.net))