Restore Passenger Rail protesters returned for the first time this year, causing major disruption on Wellington's SH1 near the Terrace Tunnel.
Traffic is beginning to slowly flow again as SH1 is cleared and the Terrace Tunnel reopened.
In a tweet, Waka Kotahi said the tunnel has reopened but warned motorists to "be patient while the congestion eases".
Earlier on Monday morning, AM reporter James Fleury said around eight protesters were blocking the lanes into the Terrace Tunnel.
"This is mid-rush hour traffic into the city right now."
Fleury said police staff arrived shortly before 8am on Monday morning, and staff can be seen taking signs off protesters sitting on the state highway.
One protester appeared to have glued their hands to the concrete, and around seven police staff could be seen surrounding the protester, working to free them from the state highway.
Newshub journalist Harry Bartle said police removed the glued protester.
In a statement, a police spokesperson said four people are "assisting police with their enquiries" and charges are "being considered"
Restore Passenger Rail spokesperson Rosemary Penwarden said Cyclone Gabrielle was a direct hit of the climate breakdown "and a direct reminder of what's to come".
"Our supporters have grown. And we are not acting alone."
Penwarden said the group will "continue to cause disruption" until the government commits to restoring an affordable nationwide passenger network.
"New Zealand’s transport emissions are the fastest growing sector, and the easiest to fix."
