WELLINGTON, May 24 (Xinhua) -- New Zealand Transport Minister Phil Twyford apologizes "unreservedly" for making a phone call on a domestic flight after the aircraft doors had shut in preparation for take-off.

"I recognize that I made the call when I shouldn't have," Twyford said, adding, "This is inappropriate for anyone, but particularly inappropriate for me as transport minister."

"I have apologized to the prime minister and offered my resignation as transport minister. She has declined my offer but chosen to transfer my responsibility for the Civil Aviation Authority to Associate Transport Minister Julie Anne Genter," Twyford said in a statement.

"I have referred the matter to the Civil Aviation Authority who will follow whatever processes they deem appropriate," the transport minister said.

Prime Minister Jacinda Ardern said that she expects all her ministers to act in accordance with the rules. "As transport minister it is even more important that Phil abides by civil aviation laws."