National is accusing Transport Minister Phil Twyford of blocking Opposition members from speaking to Transport Agency (NZTA) officials.
This is despite the fact documents show Twyford gave the green light to numerous meetings between officials and National MPs.
Documents, obtained by National under the Official Information Act (OIA), show that on eight occasions over the last 18 months Twyford recommended a meeting between officials and a National MP not go ahead.
Instead, on six occasions Twyford suggested information should be either put in writing or that written information should be requested.
There were just two occasions between February last year and June this year when Twyford recommended a meeting with a National MP be not approved.