Many employers could also be unaware their staff were suffering mental health problems.
"There isn't a broad duty of care and I'm not sure what that would mean or how far it would go.
"There's that issue of not knowing that the issue is there. Once you do know about it what do you do with that information?"
He said once an employer becomes aware of a situation the right thing to do would be to try to understand what it means in the context of the workplace.
"What can be done to support that person? What could be reasonably accommodated in terms of aspects of the work or workplace that may exacerbate that medical condition?"
Employers should be flexible with time off to help the employee recover but he drew the line at making mental health their responsibility.
That would be particularly fraught if an employer didn't know there was an issue.
"We see a lot of instances where ... there isn't a [mental health] diagnosis.
"In some instances the person themselves doesn't know they're suffering from a condition."
Mental health advocate Mike King earlier said there was no way to know if someone was suffering depression unless they told you.
"There are no signs. I have been to dozens of funerals where people have died by their own hands and the stories are the same, the story of Greg is the same. He was a funny guy, he was always there for other people, the most caring person in the world.
"Where is that in the information sheets? Where does it say to look out for the happy guy who always cares for other people, the guy with the quick wit, with the helping hand?
"It's not in any of the 'things-to-look-out-for' sheets, so all they're doing is having us looking in the wrong directions.
"There is one sign and one sign only that people are struggling and that is if they tell you."
Mental Health Foundation chief executive Shaun Robinson said depression was a very significant issue in the world.
"It's set to overtake heart disease as the major epidemic in the western world by next year, according to the World Health Organisation."
It will be more common than heart disease as a health condition, he said.
Meanwhile a former journalist said late night news presenting could take a toll.
"It is a very lonely job because the fact is, if you love being part of the newsroom, everyone's gone and you're on your own with a very small team.
"The business of the day is over - not much happens at that time and you tend to be out of the loop.
"You feel very insecure in that role because you are a presenter but everyone else is out of the building."
The source added that journalism had become an increasingly difficult job.
"It's a great job but you need to be tough now to do that job. It's confrontational now and I think the newsrooms are tougher and more is expected of everyone.
"But that's the modern workplace too, everywhere is tough."
TVNZ spokeswoman Georgie Hills would not comment on questions about Boyed's role out of respect for his family.
However she confirmed a karakia had taken place in the TVNZ newsroom today in honour of Boyed.
WHERE TO GET HELP:
If you are worried about your or someone else's mental health, the best place to get help is your GP or local mental health provider. However, if you or someone else is in danger or endangering others, call 111.
• Lifeline: 0800 543 354 (available 24/7)
• Suicide Crisis Helpline: 0508 828 865 (0508 TAUTOKO) (available 24/7)
• Youthline: 0800 376 633
• Kidsline: 0800 543 754 (available 24/7)
• Whatsup: 0800 942 8787 (1pm to 11pm)
• Depression helpline: 0800 111 757 (available 24/7)
If it is an emergency and you feel like you or someone else is at risk, call 111.
There are lots of places to get support. For others, click here.
