With peak traffic time approaching traffic built up in both directions of the expressway, stretching up to 3km while emergency services worked to clear the scene and re-open the bridge.
The male driver of the van was treated for minor cuts and abrasions.
"Just as we were finishing clearing the road we got called to the second one," an officer who attended the scene said.
A woman travelling south towards Hastings had driven into the back of the last car in the built-up queue on the Napier side of the bridge - about an hour after the first crash.
That incident led to further traffic disruption and delays.
The woman was taken to Hawke's Bay Hospital as a precaution after receiving suspected whiplash injuries.
"People need to be aware that there could be hold-ups - they need to maintain that safe following distance."
Police inquiries were continuing.