Mr Parker said serious crash investigators were continuing to piece together what happened.
No further details about the dead riders were immediately available.
The crash closed traffic through The Terrace tunnel on State Highway One - the main route in and out of central Wellington - for about 3-and-a-half hours until 4.30pm.
This caused gridlock on central city roads as cars were often moved at less than walking pace along the main city bypass and busy connecting roads, such as Taranaki St and The Terrace.
Ambulance spokesman Dan White said paramedics treated the man and the woman at the scene, attended by two ambulances and an ambulance 4WD.
Two other ambulance 4WDs were stood down before reaching the crash site.
DO YOU KNOW MORE? CONTACT THE HERALD HERE