Fears are mounting for the safety of a missing Landsdale toddler as his parents appeal for help in finding their autistic son.

Two-and-a-half-year-old Sam Trott has not been seen since he went missing from his home in Walbrook Mews at around 10.30am on Tuesday morning.

His parents Lyndal and Matthew appealed for help on Tuesday afternoon, with his mother saying she asked Sam to close the fridge door and, when she heard it beep again, again asked her son to close it before realising he was not in the house.

Workmen had been at the home and Ms Trott said one of them may have left the door open.