The number of P lab busts in the Bay has hit a four-year high.
In total, 15 clandestine P labs were uncovered in the Bay of Plenty this year but that number is set to increase with police awaiting test results on 12 other properties.
Eleven were located in the Western Bay, the latest of these were found in Katikati and Oropi during Operation Detroit which ended last week. Three labs were in Taupo and one in Rotorua.
The number of labs is up significantly on the eight uncovered last year and 11 the previous year.
Bay of Plenty crime services Detective Senior Sergeant Lindsay Pilbrow said the results reflected a hardline approach by police.
"We're happy that we're finding these labs and the work that we're doing is obviously making a difference and putting pressure on these cooks.
"The figures and the activities last week should give the public some confidence that we're doing something."
The two labs found in Tauranga this month were large operations which would seriously disrupt the supply of methamphetamine, Mr Pilbrow said.
"These labs can be of varying sizes and varying production scales but if we take them out of action they are significant blows for the groups that are running them.
"There's going to be less methamphetamine on the street and that's got to be positive."
The increase in P lab busts has also resulted in more properties needing to be decontaminated this year.
Restoring a methamphetamine contaminated house to an inhabitable state can cost from about $3000 to tens of thousands of dollars. Police this year notified Tauranga City Council of nine clandestine labs which needed specialist cleaning because of P contamination.
Last year, there was only one case. In 2010, there were four, and in 2009, there were seven.
A spokeswoman for Western Bay of Plenty District Council said several houses in the district required specialist cleaning.
New Zealand Drug Detection Agency Bay of Plenty general manager Leigh Sefton said the organisation was often contacted by the council, police, landlords and potential buyers to carry out initial testing.
The initial swab test costs $430, plus GST, and if the test came back positive a full laboratory team would be needed. This could cost between $2000 and $4000, Mr Sefton said.
Enviro Clean and Restoration operations manager Jeremy Hooper said clean-up methods and costs varied widely depending on the level of contamination.
"The costs can range from a few hundred dollars into the tens of thousands or dollars," he said.
In some instances a chemical wash-down can be all that is needed but in severe cases the house may need to be fully stripped, with building materials and linings removed and replaced.
Contamination caused by smoking or manufacturing the drug can cause skin, eye, nose and throat irritation, nausea and abdominal pain, respiratory difficulties, headaches, dizziness, feeling fatigued and difficulty sleeping, he said.