Some - such as three Te Puea mums who have 14 children between them and 30 debts totalling almost $150,000 - were struggling under loans they may never be able to pay back.
Dennis questioned how families were given access to new loans when already in debt and sometimes having no income other than Government benefits.
"Parents need to take some blame for the decision-making," he said.
"But through our ongoing dealings with homeless whānau here, there is always an element of avoidability."
His decision to speak out comes as the Government attempts to crack down on loan sharks and rogue lenders.
Commerce and Consumer Affairs Minister Kris Faafoi said people were being given loans they couldn't afford and lashed with huge penalties and fees that sent them into a "debt spiral that is very difficult to get out of".
A discussion paper released last week suggested laws could be tightened by - among other measures - possibly capping the maximum interest rates and fees lenders are allowed to charge.
Mobile trucks travelling door-to-door to sell goods have already been hit by a recent Commerce Commission crackdown that led to $1.56 million in fines and refund orders being issued.
One commission investigation into Greenfield Global, trading as KiwiOwn, led the company to late last year refund nearly $110,000 in credit and default fees to customers.
KiwiOwn likely misled customers and failed to disclose key information about credit contracts, the commission said.
Using a catalogue to sell iPads, laptops, XBox gaming consoles and even lawn mowers on weekly instalment plans, KiwiOwn proved popular with families at Te Puea now in debt to the company.
Another company popular with Te Puea families - the urban street wear chain Red Rat Clothing - has also been the subject of five complaints to the commission since 2012.
Shoppers at Red Rat can walk out with hip-hop and urban street wear clothes without paying money up front when granted approval for an instalment payment plan.
But in May this year, the commission contacted the company - which has Auckland outlets in Papakura, Manukau, Mangere and Henderson - to provide them with information "about their responsible lending obligations".
Chief executive Richard Wright said Red Rat was contacted by the commission only once and that it had since clarified its assessment process, despite already being compliant.
Families on low incomes or benefits often wanted to spread out the cost of such purchases, he said.
However, they first had to provide proof they were living at a residential address and be subjected to a credit check.
Red Rat also made reasonable inquiries about their income and food and living expenses with those who were homeless, in significant debt or who might be put into "substantial hardship" refused credit.
The commission said it had also received complaints against Cash Converters and the G-Mana/Kiwi Auto Finance Otahuhu dealership.
However, it did not provide details about the complaints or whether they were connected with the Credit Contracts and Consumer Finance Act, governing lending laws.
A Cash Converters spokeswoman said the company had spoken to the commission and was not aware of any current complaint against it, while G-Mana said it was also unaware of any complaint.
Cash Converters said it had given out hundreds of thousands of loans and payment plan deals and had never had a complaint needing formal dispute resolution.
G Mana said it had also been in business for more than a decade without any major complaints.
Like Red Rat, both companies said they carefully screened those seeking credit.
Licenced pawnbroker Lelei Finance managing director Ilaiasi Lelei also replied to Herald questions to deny the company lent irresponsibly.
As with Red Rat, Cash Converters and G-Mana, he said his company had a number of measures to help those who were under financial or personal strain while paying back their debts.
Te Puea's Dennis, meanwhile, wants to see the law strengthened.
"We have laws and regulations, but the many, many small rogue operators, are slipping through the cracks," he said.
"[They] continue to prey on the vulnerable and needy, which in many cases, ends them up as homeless, or here at the marae."
