HNZ has confirmed it issued a seven-day notice to vacate on January 17, "for various and ongoing breaches of the tenancy agreement".
"These breaches included antisocial behaviour and the use of methamphetamine at the property," regional manager Neil Adams said.
The unit is now empty pending a small amount of clean-up work on the exterior of the property and "interior remediation" for P contamination, Adams said.
It is understood the house tested positive for P in November.
Alexander said the response from HNZ to his repeated requests to have the offensive rubbish removed and the house fixed had been: "There is a process we have to go through".
He said the other tenants who were no problem were not being supported.
"It seems to me that the crackheads had more rights than the right of the other tenants to live free of this toxic contamination. Now the rats have more freedom than any of us."
Adams said the seemingly slow eviction process had been due to a communication problem.
"The did not respond to our repeated efforts to engage with them and had not moved by the date of the tenancy termination.
"Under the Residential Tenancies Act, there is a legal requirement on Housing New Zealand to follow an appropriate process."
The property is in a purpose-built complex that HNZ invited the Northern Advocate to look through when they were first tenanted in November 2015.
The two bedroom, two-storeyed homes were considered flagship houses in Whangarei, meeting a demand for smaller social houses for tenants other than families.
In mid-May the Advocate reported 22 state houses were empty in Whangarei, seven of them awaiting repair after testing positive for P.
HNZ had fixed nine of its 2000 homes across Northland since January because of P contamination.
The state housing shortage in Northland has seen the Ministry of Social Development (MSD) stump up $271,000 in the three months ending March 31 for people to live in temporary accommodation in the region.
In Northland during that time, 477 extendable weekly Emergency Housing Special Needs Grants (SNG) were made by MSD to the value of $377,343, putting 130 clients into short-term accommodation, often motels.