MILAN, Feb 22 (Reuters) - Italy's biggest bad loan manager, doValue, on Thursday posted a 19 million-euro ($21 million) net loss for 2023 as debt collections dropped 10% last year, driving revenue lower.

In a blow to collections, doValue in 2022 failed to renew an agreement to recover debt on behalf of Sareb, the "bad bank" Spain set up to clean its banking system after the global financial crisis.

The full-year loss reflects impairments doValue booked on its Spanish business.

At the end of last year, doValue managed 116.4 billion euros in bad loans, down from 120.5 billion a year earlier.

The group said 2024 would be a year of transition in which it would cut costs and invest to support growth in 2025 and 2026.

It will present a new business plan on March 21.

Healthier bank balance sheets meant levels of impaired loans remained low, limiting the need for disposals which have traditionally fed the market for bad bank loans where companies such as doValue operate, it said.

DoValue, which is active also in Greece, said it expected new contracts to manage some 40 billion euros in bad debts over the next 18 months across Southern Europe.

However, some of these deals could take longer than anticipated to materialise, preventing the company from returning to growth this year.

DoValue is "economically sound" to face the current scenario, it said.

($1 = 0.9240 euro) (Reporting by Valentina Za in Milan Editing by Matthew Lewis)