"Two days later, the committee has now sent a report back to the House stating it does not believe there are any matters needing investigation despite Opposition members pushing for the petition to be progressed.
"It is usually the convention that petitioners and government officials be invited to provide a written submission, and from there the committee decides whether or not to hear from the petitioners in person," said Ms Mackey.
"On an issue this important, and with so many signatures, I would have expected the mayor at least to have been invited to present to the committee in person.
"The National Government is showing arrogant disregard for the people of the East Coast who are deeply concerned about the possible loss of the rail line and the impact that will have on their local economy and community."
The Government has delayed a decision on the fate of the Napier-Gisborne line.
Transport Minister Gerry Brownlee would not commit earlier this year to repairing the line under questioning from New Zealand First MP Brendan Horan in Parliament.
The line was closed at the end of March after heavy rain caused three dropouts, one a 100m wide chasm, near Beach loop.
KiwiRail has said it will cost up to $4.5 million to fix the damage but other maintenance required on the line had to be taken into account.APNZ