Scientists are asking for help to find expensive earthquake monitoring equipment last seen when it was lowered to the seafloor off the coast of Hawke's Bay in 2018.

Five instruments, costing about $30,000 each, belonging to GNS Science and Columbia University in the United States, were monitoring the Hikurangi subduction zone for slow-slip earthquakes... but when they tried to recover them late last year they failed to surface.

GNS senior quake scientist Laura Wallace, spoke to Logan Church.