"We need to stay where we live, not travel around our community. If we all help the people who live near us, then everyone will be supported and we'll all keep safe," she said.
"Even helping your neighbours still needs to done without compromising your bubble, so make sure you keep two-metre distancing and follow other precautions such as hand-washing.
"If you want to help or if you need help, contact your local Neighbourhood Support co-ordinator and get involved in a group which is working alongside Police and other community agencies, and has accurate information and systems in place."
As at 9am Friday, there had been 338 confirmed cases of Covid-19, plus an extra 30 probable cases, taking the combined total to 368.
Meanwhile, the number of cases who had recovered was 37.
It was concerning to see groups being set up on social media who were not aware their advocacy would put others at risk, Casey said.
People had to make sure surplus fruit or household items were cleaned or quarantined properly before use or consumption.
A letterbox drop would be fine in normal circumstances but the virus could live on paper for up to 24 hours, so Kiwis had to be aware of the risk.
Another major concern was the number of people being encouraged to provide their private information such as their names, ages and phone numbers online.
"We definitely need to know how to contact our immediate neighbours but we recommend sharing with a small group, rather than a larger group of people that you don't know," Casey said.
"There are risks and privacy issues associated with this.
"The advantage of setting your neighbourhood group up through Neighbourhood Support is that we can then make sure your information is stored safely and provide you with advice and support."
High-level contingency planning had considered moving most non-coronavirus treatment out of one or more hospitals, should the number of cases needing hospital care surge.
Health Minister David Clark confirmed that possibility yesterday.
"Some countries facing more cases of Covid-19 are dedicating some hospitals to treating the disease, and keeping others clear for other medical care," he said.
"That approach could be used here as well, but no decisions have been taken at this stage."