Bill de Blasio donor Jona Rechnitz’s ties to accused Ponzi schemer Jason Nissen is starting to cause problems for Manhattan federal prosecutors seeking to use Rechnitz as its key witness in an upcoming bribery trial.

Defense lawyers for hedge funder Murray Huberfeld — accused of paying ex-NYC prison guards’ union head Norman Seabrook illegal bribes — demanded an “evidentiary hearing” to suss out Rechnitz’s role in Nissen’s alleged Ponzi scheme.

“The government is in possession of ample material that indicates Rechnitz’s knowing participation in this scheme,” lawyers for Huberfeld said in court papers.

Nissen, a former NYC school teacher, was busted in May and charged with running a $70 million Ponzi scheme involving “Hamilton,” Superbowl and Adele tickets.

In June, it emerged that Rechnitz may have been paid up to $8 million by Nissen for touting Nissen’s ticket business to his wealthy pals.

It’s unclear what Rechnitz knew about Nissen alleged shenanigans, but investors have since told The Post that they believe Rechnitz tricked them into investing by claiming he was one of Nissen’s largest investors.

Nissen has claimed Rechnitz never invested a penny, according to court filings.

Investors have also claimed that Rechnitz never told them about the millions fees Nissen says he gave to Rechnitz for acting as his recruiter.

Civil court documents in the case also accuse Rechnitz — the fed’s key witness in a separate probe against two NYPD cops — of threatening “to go to the feds” unless one of his wealthy friends got paid.

A lawyer for Rechnitz declined to comment.