The Gisborne District Council says the remains in four graves in the Matahiia Cemetery, near Ruatoria, have been swept into the Mata River.
A decision to disinter the 23 graves in the council-owned cemetery was made last month but saturated ground has delayed the process.
The community facilities asset manager, Terry McMillan, says heavy rainfall in the region has changed the course of the Mata River, which is now cutting into the cemetery.
Mr McMillan says descendants of the four deceased have been contacted and relatives of those buried in other plots have also been asked to remove headstones, in case of further flooding.
