The Chief Ombudsman has launched a "broad investigation" into the MIQ booking system after receiving "hundreds" of complaints.
Peter Boshier said in a statement on Wednesday afternoon about 200 complaints had been received.
There were some "common themes", he said, including that the system is unlawful, not fit for purpose, unfair and poorly managed.
"I have decided to do my own independent investigation into them all."
Boshier said the complaints had come from people around the world having trouble with obtaining vouchers or who had concerns about the booking system overall.
He said he had concerns about whether the online system is accessible and whether suitable alternatives are there for those who have difficulty using it.
This was due to the fact one of the specific complaints was those with disabilities were being disadvantaged.
The Ministry of Business, Innovation and Employment had been told Boshier would be investigating.
"I want to give the public some assurance that the MIQ booking system is working as well as it should."
"While I could investigate each of these complaints in turn, I don’t believe this is the most efficient way of addressing any underlying issues. That is why I am looking at them together," he said.
"When a new complaint comes in, my team will assess whether it should be addressed as part of this investigation or investigated and resolved individually."
As his investigation will be "broad", Boshier said it would not directly result in anyone being granted a voucher or being given priority in the queue.
Boshier's aim is to report his findings to Parliament early next year, although he said he may make statements at different stages.
He said he would be taking into account current court proceedings about the Government's operation of the MIQ system.
ACT continues call to end 'Hunger Games'
In the wake of the announcement, ACT leader David Seymour continued his call for the "Hunger Games" to stop .
He said it was "hardly surprising" Boshier was investigating the MIQ booking system, which he described as "shonky".
Seymour said those struggling to get home had been "disowned" by the Government and it needed to change.
"It’s time to stop the cruelty and restore fairness."