Ex-NRL star Alex McKinnon and his wife Teigan have welcomed their first child into the world.

The former Newcastle forward, who has been confined to a wheelchair after suffering a devastating spinal injury in 2014, took to social media on Monday - the date of the couple's first anniversary - to introduce his daughter.

Harriet Anne McKinnon was born on Sunday night. Mrs McKinnon, who has documented her pregnancy on social media, wrote on Instagram: "When 2 became 3. Harriet Anne McKinnon. 7-10-18".

McKinnon was a promising rugby league talent with the Knights when he suffered a career-ending spinal injury in an NRL match against Melbourne four years ago that left him quadriplegic.