He said there were two law changes heading for Parliament - both introduced when National was in power - but recognised more needed to be done.
"I am actively considering other ways to address the issues being faced by the tribunal".
It can't come soon enough for those who have taken complaints to the tribunal seeking prosecutions of those they claim had breached their rights.
Activist and blogger Martyn Bradbury said he was stunned to receive an email from a tribunal staff member telling him that it had no idea when his case against the police would progress.
He had been seeking a telephone conference with the tribunal and police to schedule the next steps in his case after police were found to have unlawfully accessed his data during the hunt for the Rawshark hacker.
The email sent to Bradbury stated: "The timing of a case management teleconference will depend entirely on the resources which the Government makes available to the tribunal.
"At the present time no accurate estimate can be given as to when a teleconference will be convened."
Bradbury filed his case with the tribunal midway through last year after finding police had unlawfully accessed his banking information, citing "computer fraud". The police inquiry appeared to have led to credit applications by Bradbury being handled and then rejected by the bank's fraud unit.
Bradbury, who said he had nothing to do with the Rawshark hack, said the financial stress caused by the rejected application had huge mental health repercussions.
"The stress of all this, the sense of these 'invisible hands' moving against me, culminated in severe depression and self harm with two suicidal episodes at the end of 2016."
He said the tribunal offered a chance to restore the damage done and the delay "gnaws away at you".
"It is frustrating. This is the only avenue to hold police to account."
Barrister Simon Judd, who takes prosecutions on behalf of the Director of Human Rights Proceedings before the tribunal, said the workload had led to delays which were frustrating.
"It can be very frustrating for the clients and they are waiting months or even years for a judgment. That's pretty unacceptable."
Among the cases taken by Judd was a prosecution on behalf of businessman Matthew Blomfield against blogger Cameron Slater. In that case, the hearing finished three years ago.
Judd said the chairman of the tribunal, Rodger Haines QC, had been "open with the fact they have been struggling".
In a decision last year, Haines said delays were caused by an "unprecedented increase" in cases, which had become more complex and were increasingly handled by complainants rather than lawyers.
He said there was also a need to change the law requiring him to personally sit on every hearing.
Kensington Swan partner Hayden Wilson - who represented Rachel McGregor in her sexual harassment complaint against former Conservative Party leader Colin Craig - said the increase in cases could reflect a greater awareness among the public of citizens' rights.
He said it could also be that more issues were being raised through Human Rights Commission processes, or fewer complaints were being resolved through mediation.
"Delays in any legal process are far from ideal, but it is particularly troubling in an area where fundamental rights are being considered."
It not only impacted on those taking cases but on confidence in the whole system, he said.
Wilson said the tribunal and its staff were "working incredibly hard".
"I simply don't think that they have the resources available to meet the present demand, and I can't see that demand decreasing in the near future."
Ministry of Justice tribunal service delivery manager Jacquelyn Shannon said a second chair appointed to share the case load meant Haines could share the duty of sitting on every hearing.
In the 2014/2015 financial year, the tribunal received 49 applications - but in 2016/2017 the number of applications was 94. A calendar year count of cases received, published by the tribunal last year, showed it had gone from 38 in 2014 to 93 in 2016.
There were also the two pieces of legislation - brought forward by the National Government and referred to by Sio - which were also intended to modernise the tribunal system.
Former Justice Minister Amy Adams was approached for comment through the National Party press office. No response was received.
