The Ministry of Health has begun wastewater testing for Covid-19 in Whanganui.
While testing in similar cities, such as New Plymouth, Taupō, Gisborne and Napier, has been under way for some time, it only began in Whanganui last week.
The ministry confirmed the first wastewater test in the district was on Thursday, August 19.
In a statement it said wastewater testing was an important aspect of ensuring Covid-19 is not running rife in the community.
"Any cases of Covid-19 need to be detected quickly in order to stop the virus spreading in our communities.