An inquiry into the Waikato DHB's purchase of information technology services from a California-based company is being launched by the Auditor General's office.
HealthTap was contracted to provide information technology services in 2015.
During its annual audit of the DHB's finances, the Auditor-General's office raised concerns about the procurement process.
The State Services Commission, which is already investigating allegations of wrongful expenditure of public money by the DHB's former chief executive, Nigel Murray, also asked the office to investigate.
HealthTap is an online platform and mobile app that enables people to talk to a doctor on their smartphone using the internet.
It was a top priority for Dr Murray, who resigned in October after spending $218,000 during three years on the job.
His spending included visits to HealthTap in the US, including travel worth about $20,000 in late 2015 and early 2016.
In a statement interim Waikato DHB chief executive Derek Wright said he welcomed the inquiry.
"Audit NZ had already identified that there were some issues with our procurement process for our online health service from HealthTap so we welcome this review and will give them any assistance they require.
"It's important that we learn lessons from how we did things in the past."
Acting chair Sally Webb said the board was already undertaking its own review of the HealthTap service, following its two-year trial, to see if it would be the right product for its virtual health strategy.