The Nurses Organisation says secret visits to emergency departments by Health Minister Tony Ryall, suggest he does not trust the advice he receives.
Mr Ryall has admitted he visits emergency department waiting rooms unannounced to observe the patient flow.
The Nurses Organisation says nurses have nothing to hide from Mr Ryall, but his high profile could be distracting for them.
Executive director Geoff Annals says the minister already engages with nurses through an expert advisory group and his behaviour is perceived as odd.
The Labour Party says ministers usually show basic courtesy and respect by announcing their visits beforehand.
Mr Ryall says he gets many reports from the Ministry of Health, district health boards and professional groups, but there's nothing like getting information directly from patients. He says he does not get in the way of busy staff.
Since becoming minister, he has set various targets, including cutting emergency department waiting times so 95% of patients are treated within six hours.