Ministry for Primary Industries (MPI) is actively investigating the cause of millions of pipi which washed up on Waitarere and Hokio Beaches last week.
MPI spokesperson Lesley Patston said they will check for the presence of an exotic (foreign/introduced) disease agent or pest species and biotoxins.
Its fisheries officers will keep local people, including iwi, informed on progress, she said.
"In the case of Hokio/Waitarere, the Ministry is aware of the situation and has sampling and testing underway."
Some results should be available soon, however based on sampling last week, "there is no indication of a biotoxin being present".
The public should not eat obviously sick or dead animals, including shellfish.