The Salvation Army's gambling addiction support service is worried about the increased number of online gambling sites.
The head of the organisation's gambling services division, Oasis, said it had been noticeable since the nationwide lockdown came into force.
Lisa Campbell said the rise in the number of unregulated overseas online gambling websites had coincided with the closure of pokie venues and casinos, and online availability of New Zealand Lotto and TAB services.
Online gambling companies were now advertising on social media, possibly because they saw people in isolation as a captive audience, Campbell said.
"I am sure they see social isolation as a great opportunity to expand business without any thought for the additional harm this could cause, further exacerbating the financial and mental harm on people already."
Oasis was now compiling information on online blocking tools that people can use to block internet gambling sites, Campbell said.
"We have heard from some clients who say they are really concerned about how they will cope, both financially and practically, at home with family or alone during the lockdown period, and are feeling very anxious, and some have asked for more support than normal."