Almost 850 plants with an estimated street value of $4.25million were removed from the house, on The Kraal Drive.

The South-East Asian Crime Squad and Campbelltown detectives who had received a public tip-off found a sophisticated hydroponics set-up with much of the two-storey home re-modelled to grow marijuana.

Three men were arrested soon after the raid, which took place while the house was vacant and have since been released while police continue their inquiries.

Chief Inspector Bryan Doyle had to call for more manpower to carry out the plants, which ranged in size from 1.4metres to 1.5metres high.

"This highlights the importance of people reporting suspicious activity relating to drug houses,'' he said.

Neighbours and passers-by gathered outside the house to watch police process the drug plants.

Neighbour Bernadette Mifsud was amazed at the number of plants coming out of the house.

She said she had seen the occupants bring plants to the home.

"I saw them drive a trailer straight into the garage with some plants but I didn't think it was marijuana,'' she said.

"I told my husband Charlie: `He [the neighbour] is going to do the house up nice. He's bringing all the plants up.'''

Mrs Mifsud said the residents of the house were very quiet. "We never saw them,'' she said.

She did notice that once they had moved into the house, they installed roof fans.

The Blair Athol raid was almost two days after 145 mature marijuana plants were found in a Bradbury home with a street value of about $350,000.

Campbelltown police raided the Bradbury hydro house on May10 and charged a man, 51.

Any information about a suspected drug house to Campbelltown police, 46201199 or Crime Stoppers, 1800333000.