MERYL STREEP’s  agony as her favorite nephew is facing five years on a felony rap behind bars on drug and weapons charges.

The ENQUIRER has learned that in August 2010, David Kyle Streep, 26, of New Ca­naan, Conn., was sentenced to five years’ probation after pleading guilty to felony assault charges.

But a little less than a year later he was arrested again – while still on probation – and could be forced to serve his original five-year jail term for the violation.

Police confirm that in July 2011, David was charged with driving while under the influence, posses­sion of marijuana and narcotics, and possession of a weapon in a motor vehicle.

Now Meryl is worried that David’s continued brushes with the law will reflect badly on her, and she’s considering distanc­ing herself from her brother’s family, says a close friend.

Troubled David is the son of Meryl’s brother Dana, a stockbro­ker who owns a lavish multimil­lion-dollar home in Connecticut.

According to the arrest affida­vit, cops searched David’s car after he was pulled over in 2011 and found marijuana and other drugs, as well as a billy club.

Now his family is desperate to keep him out of jail and have asked Meryl to have a heart-to-heart with her nephew.

“She doesn’t know what to do,” added the friend.

 “She’s not sure whether she should reach out and help him – or stay away completely.”