New data from credit reporting firm Centrix shows Auckland and Northland have recorded increased debt stress compared to the rest of the nation.
Business defaults are at 18 percent in Auckland and 12 percent in Northland.
Centrix managing director Keith McLaughlin said uncertainty was hampering small businesses and some may fold.
"Companies that really have their backs to the wall, mainly the small enterprises who may struggle to survive and I notice that the Auckland Chamber of Commerce's recent survey said that 20 percent of businesses expected not to survive the lockdown, so those could obviously be casualties."
Across the country, consumer credit demand has flattened, driven by the Auckland lockdown.
Despite the debt stress, credit demand in Northland increased 10 percent when it moved back to COVID-19 alert level 2 in September.
The rest of the country continued to track close to pre-lockdown levels, the Centrix report said.
Mortgage applications continued to climb but new mortgage lending remained flat.
"Whether this is a result of the lockdown delaying settlement, a signal that demand continues to outstrip supply, or an early sign of banks tightening lending criteria, remains to be seen," McLaughlin said.