A temporary manager has been appointed to oversee the running of a third rest home.
Managers have already been placed at Villa Gardens Home and Hospital in Christchurch and the Ranfurly Manor rest home in Feilding this week.
This comes after the closure of Belhaven rest home in Auckland, after an elderly resident had her mouth taped shut.
The Waitemata District Health Board says the Birkenhead Lodge Rest Home on Auckland's North Shore now is under scrutiny.
The DHB's spokesperson, Bryony Hilless, says the temporary manager will be there for at least three weeks, while concerns about management and the quality of care and treatment are investigated.
Ms Hilless says there are no immediate concerns for the well-being of the rest home's 35 residents. She says their families have been informed and there are no plans to move them.
Mid-Central Health Board revealed on Thursday that a temporary manager had been assigned to the Feilding rest home in Manawatu, due to safety problems.
The DHB's general manager of funding and planning, Mike Grant, says safety concerns were first reported in June by a consultant and investigations show that they have not been rectified.
Mr Grant says Ranfurly Manor does not have enough registered nurses to ensure an adequate level of care, but it is not facing closure at this stage.
On Wednesday, the Canterbury District Health Board appointed a temporary manager to the Villa Gardens home in Christchurch to investigate claims of sub-standard care of the elderly.