A Christchurch couple have been sentenced for their roles in a man's fatal drug overdose in September last year

Jared Croft and Janna Clarke gave the 20-year-old man a large rock of MDMA - around 10 millimetres in diameter - saying he could have it free if he took it all at once.

Croft posted the man's fatal reaction on Snapchat, and the victim was pronounced dead by paramedics later that morning.

Open Justice reports the man's post-mortem found he had taken ten times more than recreational use, as well as meth, cocaine and alcohol.

Croft was sentenced to 28 months in jail, and Clarke: 12 months in home detention.