"The key change we made in the law last year was enabling the ministry to directly prosecute. The analogy is to our employment law, where it's generally the employee who would take a case against the employer but in cases of serious breaches the law enables the labour inspectorate to take prosecutions."
He said the new compliance unit already had "a number of prosecutions under way".
"The law does give it powers to inspect where they have reason to believe that a property is substandard," he said.
But Labour housing spokesman Phil Twyford said many other substandard boarding houses were still open.
"There are dozens of boarding houses in Auckland and many of them are substandard. Most people would be shocked by the conditions that people are living in," he said.
A parliamentary inquiry into boarding houses in 2014 urged the Government to update regulations under four housing-related laws to be "more reflective of modern standards".
A Government response tabled in Parliament in 2015 said it "acknowledges that the regulation of quality is fragmented and outdated", with the main Housing Improvement Regulations dating from 1947.
"There has been no significant response by the Government to the inquiry," Twyford said.
"The way to do it is for the Government to set out minimum standards for boarding houses, and there needs to be a positive licensing regime so that boarding house operators have to apply for a licence which would make it easier for rogue operators like the owner of this one to be weeded out and shut down."