By Alberto Chiumento

(Reuters) -Italian tax police raided the offices of companies Digital Value and Olidata as part of a preliminary investigation into alleged public procurement offences, the Rome Prosecutor's Office said in a statement on Tuesday.

IT service provider Digital Value said it had learnt on Monday night that its Chair and CEO Massimo Rossi was under investigation for alleged corruption related to supply contracts signed by the company.

The company said that it "has initiated the appropriate internal investigations and has full confidence the ongoing investigations will bring complete clarity to the matter".

The Guardia di Finanza are probing alleged corruption in the procurement of IT and communication services tendered by SOGEI, an IT company fully owned by Italy's finance ministry, as well as by the interior and defence ministries, according to the statement from the prosecutor's office.

Olidata Chair Cristiano Rufini said that his company, a technology consultant, had acted correctly and was ready to cooperate with the investigation.

"We trust in the work of the competent authorities and are confident that the transparency of our actions will be clarified," Rufini said in a statement.

Trading in shares in both companies was halted after Digital Value's stock fell by 10.5% - it is indicated down by 50.3% - and Olidata's stock dropped by as much as 11.4%.

(Reporting by Alberto Chiumento, editing by Keith Weir and Emelia Sithole-Matarise)