Earthquake Commission chief executive Ian Simpson, who led the organisation through the aftermath of Canterbury earthquakes, has quit the role.
The commission said Simpson was stepping down at the end of the year to become head of another Government agency, GNS Science.
Simpson took on the role in 2010, before two major quakes struck Canterbury.
Commission Minister Gerry Brownlee said Simpson had supervised one of the biggest insurance company responses to any natural disaster anywhere in the world.
He had shown great dedication and commitment to the role over the past six years, Brownlee said, despite facing "considerable, but equally undue criticism".