A dozen dead blue penguins are reported to have washed ashore in eastern Bay of Plenty.
The Department of Conservation Department says Massey University will carry out post-mortems on them.
A Gisborne District Council member has linked the deaths to seismic testing off East Cape by Petrobras.
But DoC says it's unaware of any such link between seismic surveys and penguin mortality.
Gisborne-Whakatane biodiversity manager James Holborow says there may be a simpler explanation, because of the seasons or the La Nina weather cycle.