NZVD2016 height - EPSG:7839

WKT

VERTCS["NZVD2016_height", 
	VDATUM["New_Zealand_Vertical_Datum_2016"], 
	PARAMETER["Vertical_Shift", 0.0], 
	PARAMETER["Direction", 1.0], 
	UNIT["Meter", 1.0]]

WKT2

VERTCRS["NZVD2016_height", 
	VDATUM["New_Zealand_Vertical_Datum_2016"], 
	CS[vertical, 1], 
	AXIS["Gravity-related height (H)", up, 
		LENGTHUNIT["Meter", 1.0]], 
	ID["EPSG", "7839"]]

Data from @esri/proj-codes

{
  "wkid": 7839,
  "latestWkid": 7839,
  "macro": "PE_VCS_NZVD2016_HT",
  "name": "NZVD2016_height",
  "wkt": "VERTCS[\"NZVD2016_height\",VDATUM[\"New_Zealand_Vertical_Datum_2016\"],PARAMETER[\"Vertical_Shift\",0.0],PARAMETER[\"Direction\",1.0],UNIT[\"Meter\",1.0]]",
  "wkt2": "VERTCRS[\"NZVD2016_height\",VDATUM[\"New_Zealand_Vertical_Datum_2016\"],CS[vertical,1],AXIS[\"Gravity-related height (H)\",up,LENGTHUNIT[\"Meter\",1.0]],ID[\"EPSG\",\"7839\"]]",
  "description": "NZVD2016 height",
  "authority": "EPSG",
  "version": "9.0(10.6.0)",
  "deprecated": "no",
  "areaname": "New Zealand",
  "extent": {
    "slat": -55.95,
    "nlat": -25.88,
    "llon": 160.6,
    "rlon": -171.2
  }
}