Two cannabis factories growing 900 plants with elaborate equipment have been discovered hidden in separate houses.

Gardai raided a property in Mount Anville Wood in Stillorgan, south Dublin, on Monday and found all of the upstairs was being used for the drugs enterprise, with a pot-growing system in each of the four bedrooms.

Some 500 plants and several kilos of cannabis grass were discovered while the rooms were fitted out with high-density lighting systems, reflective wall coverings, ventilation and extraction systems.

A 33-year-old woman was arrested at the scene. The search was sparked by the arrest of a 33-year-old man at around 1pm by officers targeting drug-dealing in the neighbouring Blackrock area. The pair were being held at Blackrock garda station under Section 2 of the Drug Trafficking Act.

They stopped and searched a car at Drummartin Link Road, also in Stillorgan, and found five kilos of cannabis grass in the boot. The total value of both seizures is estimated to be 600,000 euro.

In a follow-up search another elaborate factory was discovered in a house on Headford Road in Kells in the early hours of Tuesday morning. The property had been modified to accommodate the operation, with the electricity supply bypassed and an air extraction system in place.

Gardai from the Meath divisional drugs unit seized 400 cannabis plants, three kilos of cannabis herb and cultivating equipment - valued at around 200,000 euro. Two males aged 16 and 21 were arrested and were being detained at Kells garda station under section 2 of the Drug Trafficking Act.

Meanwhile, three men were being questioned over the seizure of around 82,000 euro of cannabis in the capital. Officers from the Garda National Drugs Unit and Organised Crime Unit stopped and searched a car and a van on the Ninth Lough Road in west Dublin at about 7pm on Monday.

During the search - part of an ongoing operation targeting the sale and supply of drugs in the area - they discovered 7kg of cannabis herb. Three men, aged 31, 35 and 43, were arrested and taken to Clondalkin garda station, where they are being held under Section 2 of the Drug Trafficking Act.

Justice Minister Dermot Ahern said there was a significant drugs industry out there that needed to be dealt with. He added: "As we found with some of the seizures of cocaine, heroin and indeed the so-called legal highs, there is a significant level of (drugs) industry out there, which we have to deal with and take out."