The DHB is about to review the controversial app, believed to have cost the health board more than $17 million and which has failed to attract the targeted number of users.
Powell said the approval process for the initiative had been "driven managerially, rather than clinically".
"It has taken place without the normal clinical scrutiny that would occur over the use of new health technology, especially one that has been developed in a fundamentally different health system, and without apparent regard to a similar new technological device developed by GPs in Waikato."
It's understood the DHB was already working with Pinnacle Midlands Health, which represents 400 GP doctors across the region, toward sharing their My Indici system before Dr Nigel Murray was appointed chief executive at the DHB.
Murray resigned last month after an investigation into his expenses found claims associated with women that were not work-related.
"It's also not clear whether the DHB's management and board investigated other issues in the course of the rapid approval process, such as the potential for conflict of interest and so on, and this is something the minister might also like to be reassured about," Powell said.
In Murray's 2016/17 salary performance targets, he was to have demonstrated five key virtual health targets including:
• a reduction in outpatient attendances at Waikato DHB of not less than 10 per cent
• uptake of virtual health by Maori in at least three projects
• and that six departments would be operating virtual services to access DHB specialists on the part of primary care.
It's not clear if Murray achieved these outcomes but they attracted a 12 per cent weighting in his overall performance targets.
Powell believed building a key performance indicator around start-up technology was unwise.
"It's very surprising that the board chair would agree to a KPI that would involve the introduction or implementation of a new piece of technology that was untested in terms of its relevance to the New Zealand health system."
Powell said technologies depended on particular health systems and what might work in one health system may not work in another.
"The fact that a new technology is being introduced and linked to the CEO's remuneration should have made the board chair much more diligent of potential conflict of interest."
A DHB spokeswoman said no conflicts of interest were registered by either board members or staff including the chief executive, over HealthTap.
Board chairman Bob Simcock said KPIs were set by the entire board not the chairman.
"Initial proposals come from the Remuneration Committee and final decision is made by the board not the chair.
"If Ian Powell has any evidence of a conflict of interest he should present it."
Simcock added the DHB would be "very happy to respond to the Minister about any questions he may have" on HealthTap.
He previously said the HealthTap proposal was not rushed and that the board would not have agreed to it if they were not convinced by it.
Simcock said the board carried out its due diligence properly and the resulting decision followed many months of evaluation by staff.
