U.S. Sen. Rand Paul is calling for an end to the Republican-on-Republican “smear” campaigns he’s endured in the party’s crowded 2016 presidential field.

“It’s one thing if they want to support another candidate. It’s another thing to be putting out blatant falsehoods and smear ads,” Paul said in an interview yesterday on Boston Herald Radio’s “Morning Meeting” show.

“I don’t think we should be doing business with groups that are doing smear attacks on other Republicans,” he said.

The Republican firm Black Rock Group, which worked on an ad attacking Paul’s foreign policy record, is also reportedly tied to a Super PAC being backed by Senate Majority Leader Mitch McConnell.

The fellow Kentucky senator’s office has said he wasn’t aware of that “activity,” according to Politico, but it has made for an awkward situation as the cramped GOP field for president puts more boots on the ground in New Hampshire, Iowa, South Carolina and elsewhere.

“I’m going to definitely be letting my voice be known” on this, Paul said. He added that he’ll be “sitting down with whoever is in charge” of the ad.

During a 10-minute interview on Herald Radio, Paul also hailed this week’s federal appeals court decision ruling the government’s bulk collection of phone data is illegal, though he reiterated that he feels it is also unconstitutional — a step the court didn’t take.

“But ruling it illegal is still a big step. What they’re saying is the government broke the law,” the Libertarian-leaning senator said. He called the mass collection a “weak weapon” for tracking down potential terrorist threats.

“It’s haphazard. It makes the haystack so big that we get lost in the haystack and we never get to the needle,” he said. “We’re spending so much time gathering everybody’s phone records, we’re not spending enough time specifically going after people.”

Paul, however, did not wade into the “Deflategate” controversy surrounding New England Patriots quarterback Tom Brady, who investigators said this week was “generally aware of the inappropriate activities,” deflating game-day footballs.

Paul said he met Brady at last weekend’s Kentucky Derby, and his wife has been happily “trotting” out a photo she took with the four-time Super Bowl champion.

“I’m afraid my family is already biased, pro-Tom Brady,” he said.

Paul remains in the top tier of Republican candidates who all fare well against Democrat Hillary Clinton in New Hampshire, a new WMUR/UNH poll shows.

Paul, Jeb Bush and Marco Rubio all beat Clinton by at least 4 points in the poll.

The GOP’s Ted Cruz, the poll adds, is only 1 point behind Clinton.