"Imagine - during the drought in 2013 the average Northland dairy farmer lost $100,000 without the payout being half of what it once was," Ms Jonker said.
Fonterra's forecast payout had dropped from $8.75 per kilogram of milk solids in February 2014 to $4.60 in May this year.
"I don't think people realise just what an effect this will have," Ms Jonker said.
"Sooner or later it will have a flow-on effect to Auckland and then the Government will sit up and take notice."
It was not just farmers but also suppliers, contractors and rural communities feeling the pinch.
"We are trying to ensure there are people in place that talk to farmers and help them see there's a way forward," she said.
There were just over 1000 dairy farmers in Northland.
Whangarei District Councillor Greg Martin farms at Ruatangata West and had been counselling several local farmers through tough financial and emotional times.
"A lot of people, when prices were going up, bought the farm next door or expanded so debt went up," he said.
He said the issue of farmers' mental health was still often skirted around.
"Mostly that's kept pretty quiet. There's been a suicide in Northland recently but it's kept quiet.
"Farmers need to identify anyone they think might be under too much stress. Sometimes it's relatively easy to fix with good advice, management, some assistance and a bit of a break."
Federated Farmers dairy industry group chairman Andrew Hoggard said most farmers had not felt the dropping cashflow effects until the start of this year due to "top up" carry over payments from the high payout 2013/2014 season.
"The pain didn't start setting in until earlier this year," he said.
"The toughest time is going to be this winter."
-Call 0800 787 254 for support or: northland.rural-support.org.nz
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.