ROME (Reuters) - Italy’s Interior Minister Matteo Salvini on Tuesday urged the upper house Senate to reject a request by judges to put him on trial for alleged kidnapping after he refused to let migrants disembark from a rescue ship, saying he had acted in the public interest.

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His appeal is likely to cause strains with his coalition partner, the 5-Star Movement, which has always presented a squeaky clean judicial image and lambasted lawmakers who try to use parliamentary privilege to avoid legal action.

A special tribunal which reviews investigations involving government ministers last week called for Salvini to stand trial for alleged abuse of power and kidnapping over his role last year in detaining some 150 migrants on board a rescue boat for a week.

A Senate committee is due to meet on Wednesday to start discussions on whether to lift Salvini’s parliamentary immunity with a vote expected by the end of February.

Its recommendation will pass to the full Senate for review, with 5-Star lawmakers holding the balance of power in both the commission and the chamber.

In a letter to Corriere della Sera newspaper published on Tuesday, Salvini, who is also head of the far-right League party, urged the upper house to reject the request.

Citing constitutional law, Salvini said the Senate could protect ministers if they had acted in the public interest.

“This is not about me. ...Fighting illegal immigration is of pre-eminent public interest,” Salvini wrote. “I am convinced I acted in Italy’s best interests and in full respect of my mandate. I would do it again.”

His request puts the 5-Star, which has broadly supported Salvini’s migration policies, in a tight corner as tensions grow between the coalition parties.

5-Star built its support partly on the back of its fierce campaigns against parliamentary abuse and in the last legislature, when it was in opposition, it demanded that ministers under legal investigation should resign.

Salvini, who faces up to 15 years in jail if found guilty, indicated last week that he would be happy to go on trial -- a suggestion that gave 5-Star lawmakers political cover to vote for his parliamentary immunity to be lifted.

That cover has now gone and there was no immediate comment from the 5-Star leadership on what stance it would adopt.

Italy has taken in more than 650,000 boat migrants since 2014, but the influx has slowed dramatically since the new government took office last June and shut its ports to rescue boats that pick up migrants off the coast of Libya.

The stand-off over the 150 migrants aboard the Diciotti coastguard ship last August signaled the government’s new hardline approach. The group of refugee seekers were allowed to land after the Roman Catholic church, Ireland and Albania agreed to take care of them.