Residents of Moruben Road in Mosman say they are "shocked" to learn of a drug bust in the dress-circle street.

Acting on a tip off, NSW Police on Wednesday morning raided a home on the street overlooking Balmoral Beach where they allegedly found 300 mature cannabis plants in what they described as an "elaborate" hydro house set up.

Police described the house on Moruben Road as an 'elaborate' hydro house. Credit:Sally Rawsthorne

The home raided by police was sold for $6.4 million in August last year.

Police on Wednesday night remained at the home, with no arrests or charges made yet. Nobody has been interviewed in connection with the alleged drugs.