SH1 near Johnsonville is now fully open after three Restore Passenger Rail protesters forced its closure after climbing atop a gantry.
The protesters initially forced the closure of the southbound lanes at about 9:30am and then later closed both lanes.
Waka Kotahi says both lanes have now reopened and warned motorists of some delays.
Protesters put up a large banner issued to the Transport Minister reading: "Michael Wood we need to talk".
Spokesperson Rosemary Penwarden planned to urge MPs at a select committee inquiry into the future of Aotearoa's inter-regional passenger rail to commit to restoring an affordable nationwide passenger rail system.
"The current New Zealand Rail Plan includes freight and tourism, but very little passenger rail. Successive Governments have made passengers take the back seat," she said.
"People like us have been civilly sounding the alarm for decades and been totally ignored."
But politicians refused to hear from protesters streaming into the Select Committee from the top of the gantry.
Penwarden believes those in Government are "not fulfilling your duty of care" to Kiwis.
"Transport emissions, the fastest growing contributor to New Zealand’s emissions, can be solved. An affordable, accessible nationwide passenger rail system is part of the solution."
Their latest demonstration marks the third week of protests after previously causing the closure of the Mt Victoria Tunnel, the Terrace Tunnel and a section of Transmission Gully.
