Telecommunications users lobby group's chief Ernie Newman has announced his resignation.
Newman will step down in late September after 11 years with the Telecommunications Users Association of New Zealand (TUANZ).
The Government's decision last week to regulate mobile termination rates convinced Newman it was time to move on.
"It's a bit scary, but I know it's the right thing to do."
"I'm going out on a bit of a high with another regulatory notch in the belt and while I've still got the time and energy to put into something else," he said.
Newman said he was unsure what his next move will be, but was open to job offers.
"Now that I have made the commitment to go I can start to think about what comes next," he said.
TUANZ represents the interests of about 450 telecommunications customers.
TUANZ chairman Pat O'Connell said in an email to members: "it goes without saying that we all owe him a huge debt of gratitude for his tireless efforts over the past 12 years."
"I know that Ernie saw (the minister's regulation of mobile termination rates) as a natural point at which to make his decision to move on, and I respect his wishes."
O'Connell said the board would address the issue of a replacement shortly.