GDANSK, April 25 (Reuters) - Poland's largest telecoms operator Orange Polska on Tuesday posted a 116% jump in first-quarter net profit to 270 million zlotys ($64.5 million), far better than expected, boosted by sales of idle assets.

Analysts had expected the unit of France's Orange to earn 180 million zlotys. Revenue grew 7% to 3.14 billion zlotys.

The company sold properties no longer in use due to the technology switch from copper to fibre networks, Orange Polska Chief Executive Julien Ducarroz said in a statement.

"Our transformation has accelerated in the areas of phase-out of legacy technologies and unused assets," he said, noting that such sales have been "particularly successful" in the quarter.

The average revenue per order (ARPO) and number of convergent customers, who experience phone calls, email, messages and social media posts via Orange Polska in an integrated way, continued to grow, the company said.

The growth of customers using single services slowed, an issue the company is taking steps to address, it added.

Despite what Ducarroz called a "good start to the year," he said "double-digit inflation will continue to affect our operating costs."

The management board

affirmed Orange Polska's 2023 forecast

, which assumes a low single-digit rise in full-year revenue and flat or low single-digit gain in Earnings Before Interest, Taxes, Depreciation and Amortization including leases (EBITDAaL).

Capital expenditure is expected to fall within 1.5 billion to 1.7 billion zlotys, compared to 1.7 billion zlotys in 2022.

($1 = 4.1863 zlotys) (Reporting by Patrycja Zaras Editing by David Goodman, Mark Potter and Richard Chang)