The family of a teenage rugby league player have made the heartbreaking decision to switch off his life support after he was critically injured during a weekend junior match in southern NSW.

Murrumburrah High School student Lui Polimeni, 15, was concussed during a tackle and collapsed on the field as his team, the Gundagai Tigers, took on the Tumut Blues in an under-16s match in Gundagai on Sunday.

Lui Polimeni, left, pictured with his father and brother. Credit:Facebook

The game was immediately stopped and Lui received medical treatment on the field, before he was flown to Canberra Hospital in a critical condition.

He was placed in an induced coma, as his family kept a vigil at his bedside.