Police say a woman was caught trying to sneak her common-law-husband out of a Mexican prison in a suitcase following a conjugal visit.

A spokesman for police in the Caribbean state of Quintana Roo says staff at the prison in Chetumal noticed the woman seemed nervous and was pulling a black, wheeled suitcase that looked bulky.

Spokesman Gerardo Campos said on Monday that prison guards checked the bag of 19-year-old Maria del Mar Arjona and found inmate Juan Ramirez Tijerina curled up inside in the foetal position.

Ramirez is serving a 20-year sentence for a 2007 conviction for illegal weapons possession.

Arjona was arrested and charges are pending.