Auckland-based property manager Rachel Kann told a social services select committee last month she routinely asked for bank statements.
"I don't just want to put a tenant into a property and no sooner have they been put in they can't afford the rent," she said.
"They're paying somebody's mortgage and I see a lot of people who are low socio-economic and their bank statements literally will read, 'KFC, McDonald's, the dairy, KFC, McDonald's, court fine', trucks that they buy, goods that they can't afford. You know, I see a lot of mismanagement of money."
But Twyford told Stuff that landlords had all the power in the current market amid "a terrible shortage of rental properties".
"I don't think there are many people who'd think it would be acceptable for a property manager to request the bank records of a prospective tenant and then pass judgment in the media about someone's spending habits."
Property managers or landlords who requested such information were skating "very close to the line of discrimination".
"A credit check is allowed under the law," he said.
"But the law is very clear that landlords are not allowed to discriminate on the basis of, for instance, employment status, so asking for a pay-cheque or payslip is sailing very close to the line."
Despite Twyford's condemnation, the Government's Ministry of Social Development suggests prospective tenants produce bank statements to help secure rental accommodation.
"If you're in paid work, ask your employer to give you a letter stating that you're employed in a permanent or long-term job," its "becoming a tenant" section reads.
"Or, you could show your landlord your bank statement with regular income."
The Herald has sought comment from Social Development Minister Carmel Sepuloni about whether she endorses this advice.
The Real Estate Institute of NZ and Property Investors Foundation also said checking bank statements was unnecessary.
"The focus needs to be around ascertaining whether a tenant has stable employment and can pay the rent, not whether they spend their disposable income on KFC or Uber Eats," REINZ chief executive Bindi Norwell said.
The NZPIF also did not believe it was necessary for landlords to view a prospective tenant's bank statement.
"The main ways we advise NZPIF members to quality check prospective tenants is through a credit check, looking up Tribunal Orders online and checking with previous landlords or current landlords if the tenant allows," executive officer Andrew King said.
Norwell said the Government should introduce regulations to oversee how landlords and property managers check credit, while King wanted landlords to be given more power through the Tenancy Tribunal to recover rental arrears faster.
For his part, Chris, who accompanied the Wellington woman on her search for houses, believed landlords were asking for bank statements because new government regulations were squeezing their profit margins.
The statements were then used as a negotiating tool.
He described how, at another meeting, a different landlord browsed the woman's statements then told her she could afford to pay a higher rent than he was asking.
"Last year there was a big thing going around with landlords asking tenants 'how much are you actually willing to pay to get a property?'"
"We feel this is the next step - no longer are they asking how much are you willing to pay, they are now looking at your bank accounts and going, 'Oh, this is how much you can pay'."
