"Those shoes are quite moving," she said. "The idea that we have lost 600 New Zealanders in the last year - I find absolutely devastating.
"Because for every one of those people there is a ripple effect in our families and our communities."
Ardern re-committed to reviewing mental health services if in Government, and said she wanted mental health teams in every secondary school in the country.
She said she wanted to eventually bring the number of suicides in New Zealand down to zero.
"Because anything else suggests we have a tolerance for loss to suicide in New Zealand."
This afternoon, the Labour leader is expected to outline what she would do in her first 100 days in government.
Labour's Wellington branch is holding a rally at the 1500-seat St James theatre, which is close to full.
Ardern will speak at the event, saying what her priorities would be if she becomes Prime Minister on September 23.
There will be a performance by Wellington bands The Black Seeds and Fat Freddy's Drop, and the Phoenix Foundation. The supergroup is called Stardust - the term used by National leader Bill English to describe Ardern.
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 police immediately on 111.
Or if you need to talk to someone else:
• LIFELINE: 0800 543 354 (available 24/7)
• SUICIDE CRISIS HELPLINE: 0508 828 865 (0508 TAUTOKO) (available 24/7)
• YOUTHLINE: 0800 376 633
• NEED TO TALK? Free call or text 1737 (available 24/7)
• KIDSLINE: 0800 543 754 (available 24/7)
• WHATSUP: 0800 942 8787 (1pm to 11pm)
• DEPRESSION HELPLINE: 0800 111 757
