Describing the scene as the medical air was shut down for the first time, they said: "Immediately all the alarms at the incubators for the babies went into alarm. Chaos ensued.
"It was switched back on within a short period of time, but when work resumed it was switched off again.
"Again all the incubators went into alarm because medical air was lost to the babies, and immediately they brought the pressure back up again.
"There was total confusion."
The whistleblower claimed to overhear maintenance staff complain that the blueprints for the hospital buildings were inaccurate and out-of-date.
"The medical pipes were not marked. I also heard them say that the backup system failed, and if any of the backup bottles were to have failed during the night at any other time they would not have worked and someone might have died."
A spokeswoman for Waikato DHB confirmed its property and infrastructure team carried out shutdown work on Thursday to enable a new medical gas pipe supply to the newly refurbished Ward E5 Waikids Medical Ward.
"The work was planned well in advance and a risk mitigation plan put in place. Property and Infrastructure worked closely with NICU staff and at any time, under their instructions, work could be stopped, and in fact was," she said.
"When we felt this isolation was not going as planned, we reverted back to the original state and suspended the shutdown.
"At no time were any infants' lives put at risk."
The work was completed on Friday, she said.
"Waikato DHB can confirm we received an incident complaint form from a staff member on Friday which we will investigate."
