Raids of eight rental properties uncovered the most sophisticated grow house network in the capital's history and disrupted a highly sophisticated drug syndicate that had operated in the ACT for up to six months, ACT Policing said.

The discovery of about 148 plants and a hydroponic set-up at a Kaleen home in mid-June triggered Operation Armscote.

Detective Sergeant Richard Gough said evidence discovered at that house led drug team members to search nine more houses across the territory, most in the northern suburbs, in recent weeks, including two properties raided on Wednesday morning.

One of those properties was a grow house, while another, where police allegedly seized about 13 kilograms of dried cannabis and a large wad of cash, belonged to a person of interest. No arrests were made on Wednesday.

Houses in Calwell, Downer, Harrison, Kaleen, MacGregor, Nicholls and Weetangera had extensive hydroponic set-ups. Another Calwell property was being turned into a grow house.

"Never before in ACT Policing history has there been this many grow houses identified in such a short space of time that have all obviously been linked to the one organised crime syndicate," Detective Sergeant Gough said.

Police said the grow houses shared similar equipment, which indicated they had been been set up by the same criminal group.

Detective Sergeant Gough would not comment further on the alleged links to organised crime, but said there did not appear to be any connection to bikie gangs.

He said all the properties were private rentals and people who leased them had used false identification and often reached a monthly lease agreement with the owners.

They had also paid a large bond and many had repeatedly delayed their rental inspections in recent months, police said.

Organisers appeared to have set up the house before they moved out and "put people to look after crops at premises", Detective Sergeant Gough said. So far, all those people had been Asian and none were originally from the ACT.

The six people charged over the grow houses were each charged with numerous offences related to participating in a criminal group and cultivating cannabis. They are now before the ACT Magistrates Court.

Police expect further charges will be laid and indicated more properties would be raided in coming weeks.

Detective Sergeant Gough said owners of the properties where the growing operations had been discovered were "very distraught".

"The properties have been completely trashed inside; there have been holes in the walls, power's been re-routed."

The damage prompted Real Estate Institute of the ACT spokesman Craig Bright to warn landlords of the perils of leasing properties privately through online listings and social media.

"There have been circumstances in the past where insurance companies will not cover these incidents," he said.

"And also, depending on the nature of the incident, whether it's violent crime or a major health risk, they could also be classified as a stigmatised property and that then has to be registered for a seven-year period."

Mr Bright encouraged property owners to only lease their homes thorugh a professional property manager, as the knock-on effects for landlords involved would be "quite dramatic".

"Property owners should show extreme caution, because it doesn't only affect the owners, it affects the neighbours and the whole street ... it's the whole social dislocation aspect as well."

Police believed more houses in the ACT were being used to grow illegal cannabis crops and encouraged any property owners who suspected they had been targeted to come forward.

They also urged residents to keep an eye out for suspicious behaviour at homes in their street and to report anything untoward to Crime Stoppers.

That included vehicles coming and going at odd hours, the sound of water running or noises from electrical equipment, garbage bins that had no't been put out and overgrown gardens.

Information to Crime Stoppers, 1800 333 000 or at act.crimestoppers.com.au.