(Adds comments from companies and Scaroni's lawyer)

MILAN, July 27 (Reuters) - Italian oil major Eni , oil services group Saipem and former Eni CEO Paolo Scaroni have been ordered by an Italian judge to stand trial in an Algerian corruption case.

The long-running case revolves around allegations Saipem paid intermediaries around 198 million euros ($218 million) to bag contracts worth 8 billion euros with Algeria's state-owned Sonatrach.

Saipem has previously said the allegations relate to events that took place up to the beginning of 2010.

In statements on Wednesday, Eni and Saipem said they were confident they would be able to prove the allegations were groundless.

A lawyer representing Scaroni, CEO at Eni for nine years to 2014, said his client was innocent.

"We are sure the court will recognise this as the judge in the first preliminary hearing had done," said Enrico de Castiglione.

A decision by a judge last year that Eni and Scaroni should not be sent to trial was overturned by Italy's top appeals court in February.

When Scaroni was CEO, Eni controlled 43 percent of Saipem.

Under Italian law, companies are responsible for the actions of their managers and can be fined if found guilty.

The corruption trial is scheduled to begin in Milan on Dec. 5, legal sources said.

Saipem, one of Europe's biggest oil contractors, is currently controlled by Eni and state lender Cassa Depositi e Prestiti.

($1 = 0.9098 euros)

(Reporting by Manuela D'Alessandro and Stephen Jewkes; Editing by Francesca Landini and Mark Potter) ((stephen.jewkes@thomsonreuters.com; +39.0266129695; Reuters Messaging: stephen.jewkes.thomsonreuters.com@reuters.net))