UPDATED 12.54pm Police have come under fire after being found at fault for the bungled handling of a missing Hamilton mental health patient who went on to drown himself in the Waikato River.

The Independent Police Conduct Authority has upheld all five complaints from the family of Nicky Stevens, a patient under compulsory care of the Waikato District Health Board's Henry Bennett Centre.

The Authority's found the Police Northern Communications Centre staff handling of the initial missing person notification from the centre was inadequate and did not comply with police policy.

It's also found the Waikato District command centre did not "provide effective oversight of the missing person event".

Yesterday, Mr Stevens' family met with Waikato police commander Superintendent Bruce Bird who apologised for the failings and discussed ways they are now improving their systems.

Nicky's father, David McPherson, said it's a tragedy that could have been avoided.

"What really hurt was that had the police done the job they were supposed to, there's a good chance he could still be with us."

Mr McPherson, said while a police apology won't bring his son back, it does give them some closure.

"It's bittersweet. We're pleased that the IPCA have upheld our complaint against the police and that the police have accepted all the findings."

Are you affected by an issue in this article? Here's where to get help:

• Lifeline: 0800 543 354 (available 24/7)
• Suicide Crisis Helpline: 0508 828 865 (0508 TAUTOKO) (available 24/7)
• Youth services: (06) 3555 906
• Youthline: 0800 376 633
• Kidsline: 0800 543 754 (4pm to 6pm weekdays)
• Whatsup: 0800 942 8787 (1pm to 11pm)
• The Word
• Depression helpline: 0800 111 757 (available 24/7)
• Rainbow Youth: (09) 376 4155
• CASPER Suicide Prevention
If it is an emergency and you feel like you or someone else is at risk, call 111.