NGC chairman Michael Stiassny told the NZX last Friday afternoon of the board changes, which will see former NGC chief executive Richard Bentley, Rick Bettle and former Labour cabinet minister Fran Wilde retire on September 30, as well as current Vector chief executive Mark Franklin.

"With NGC wholly owned by Vector and delisted as a share issuer, the role and function of the NGC board has fundamentally changed," said Stiassny.

"As NGC's businesses are in the process of being merged with those of Vector, the governance functions performed by the NGC board will become the responsibility of the Vector Board as part of its oversight of the wider Vector Group."

Stiassny said that independent directors Bentley, Bettle and Wilde had served NGC and its shareholders with distinction, especially during the ownership change processes over the past year.

NGC continued to be listed on the NZX debt security market board (NZDX) as an issuer of fixed interest rate bonds, he added.

Vector last month successfully acquired all of NGC and listed on the NZX through a NZ$592 million IPO, representing 24.9% of the group.