As jury selection began Monday in the new bribery trial for former state senator Malcolm Smith, his co-defendant was slapped with ​new charges — for allegedly tampering with a witness.

Prosecutors say former Queens Republican Vice Chairman Vincent Tabone on May 23 confronted Philip Ragusa, who then chaired the borough’s GOP party, at his home and tried to convince him not to testify when Tabone and Smith were on trial earlier this year for trying to fix the 2013 mayoral race.

That White Plains federal court proceeding resulted in a June mistrial following the feds’ late release of more than 92 hours of recordings – including 28 hours in Yiddish yet to be translated.

A superseding indictment in the $200,000 bribery case now alleges Tabone spoke to the “county chairman,” who is not mentioned by name, while the chairman was “failing in health” and “resting in bed” and “encouraged” him not to testify. Tabone also allegedly claimed “no court” could “force” Ragusa to testify. The death-bed conversation took place an hour before Ragusa was supposed to give a deposition to prosecutors.

Ragusa, who was never charged with wrongdoing, was expected to eventually testify at the trial in defense of another co-defendant, former Councilman Dan Halloran (R-Queens), but died in June of leukemia.

Halloran refused the mistrial and was convicted in July by a White Plains federal jury of masterminding the failed bribery scheme to get Smith, once one of the state’s most powerful Democrats, the Republican mayoral line.

At the time of the first trial, Smith was a state senator and seeking re-election. But he lost the September primary and his 14 years in office ended Wednesday.

Smith’s attorney, Gerald Shargel, said in court that he’d allege entrapment, as he did in the first trial.