An investigation has been launched after a three-year-old boy was injured when a door fell on him at a sushi shop.

Barbara Ding was at The Chancery Sushi Train restaurant in central Auckland last Tuesday night, when a broken restaurant door fell on her son Harry.

She's now worried her son may have suffered psychologically as he is beginning to have nightmares.

Auckland Council are investigating and restaurant staff are apologetic, but say they couldn't get anyone to fix the door over the festive period.

Ms Ding said that's not good enough and the door should never have been left to just sit there as an accident waiting to happen.

She claims the owners told her that the door would be alright because it was big and heavy, and that no one would be able to lift it.