A Bronx state senator is being eyed by the Board of Elections for his handling of a $200,000 loan he received from a Long Island dentist to fill a campaign budget hole, The Post has learned.

Sen. Luis Sepulveda obtained the loan, at 4 percent interest, from Dr. Efraim Zak in July 2017 to bankroll his special election to the Senate in April 2018, records show.

It is unusual for a candidate to take that large a loan from an individual. But it is legal if paid back on time.

The loan was arranged by Sepulveda’s campaign treasurer, Oshrie Zak, who is Efraim’s brother, a source close to the senator said. The state senator has known the siblings for years, the source said.

A Bronx political insider said Sepulveda obtained the $200,000 loan to show strength as the Bronx Democratic Party weighed whether to give him the nomination for the Senate seat, which it did.

But Sulpeveda didn’t pay the loan back until September 2018, five months after the election, according to records filed with the state elections board.

Board of Elections spokesman John Conklin claimed that the failure to pay off the loan on time was a “violation,” in effect converting the money into an illegal, over-the-limit campaign contribution. Donations from an individual are limited to $11,8000 for a Senate general election.

“Since Sepulveda was a candidate in the April 24, 2018 Special Election to fill the vacancy in the 32nd Senate District, I would argue it became an over [the limit] contribution when it wasn’t repaid by April 24th. Had he made his filings on time, he would have been informed it was an over [the limit] contribution,” Conklin told The Post.

“It was repaid in September. It would be up to the [board’s] Enforcement Counsel to determine if the violation was intentional and therefore subject to a possible fine,” Conklin added.

Sepulveda, in a statement, said he abided by all rules regarding the loan.

“The loan was made to the committee in full accordance with Board of Elections guidelines and was repaid in full,” he said.

“We expect the committee has satisfied all of the Board’s requirements.”