Four people have been arrested after Toronto police discovered a marijuana grow-operation inside a north Scarborough home on Tuesday.

Officers found 600 plants growing in the basement and upstairs bedroom of the house on Starry Crescent, near Steeles Avenue East and Markham Road. The plants have a street value of about $600,000.

Police made the find after receiving a tip that a strong smell of marijuana was being emitted from the home.

Some residents in the community were shocked to learn of the drug bust.

"I don't know what to think. Everybody's pretty quiet and keeps to themselves here," said neighbour Gisel Kent.

"I'm not very happy about it," said resident Mike Martin. "I have two daughters, aged four and six, and I'm not happy to see any of that type of thing in any neighbourhood, but it hits close to home when it's just down the road."

Police said the perpetrators had been stealing hydro, and it was just a matter of time before a fire broke out.

Det. Sgt. David Malcolm said the force will continue to get its message out to residents that they should keep an eye out for signs of grow-ops in their communities.

"It's exactly what we've been explaining to neighbourhoods that are prone to having marijuana grow operations," Malcolm told reporters.

"They'll be noticing a smell, they may be observing some activity that is suspicious to them, and what we tell them is 'call the police, let us know that you suspect something's going on in your neighbourhood.'"

Police, who described the grow-op as a medium-sized operation, were obtaining a search warrant before conducting a thorough search of the home.

With a report from CTV's Jim Junkin