A homeless man whom cops found sprawled out on a Manhattan subway train punched an NYPD sergeant who had offered to help him, ­police said Thursday.

Jose Gonzalez, 40, was lying down on a northbound 6 train early Wednesday morning when he lunged at a sergeant ­offering him aid from the Department of Homeless Services, ­according to police.

Gonzalez turned belligerent and slugged the officer in the head. He was arrested and charged with assault and resisting arrest. The officer was taken to a hospital and later released.