And Williamson has called for the party to re-open nominations for the National Party board, saying others would have put their names forward had they known earlier.
Goodfellow announced this morning he would retire as president at the party's annual conference in August – but still intended to seek re-election as board director.
There are three spaces on the board as the terms of Goodfellow, Rachel Bird and Sir Graeme Harrison end, but all three said they were seeking re-election. No other names were put forward by the time nominations closed on June 21. The president is elected by the board after the party's membership elects the board members.
"A lot of people didn't put their names forward because, as David Carter has found, it's impossible to get rid of [Goodfellow]. But they wait until it's all closed and then 'Surprise!'
"After nominations closed on June 21 and nobody could do anything about it, he has now declared he's not seeking to be president any more but is going to stay on the board to 'give help and guidance' to whoever the new president is.
"That is just internal self-management of the very worst I've ever seen. The straight process of that is shockingly internal management of keeping the old boys network running. Kim Jung Un could learn a thing or two, he really could."
A spokesperson for the National Party said nominations will not re-open. Goodfellow said he did not want to respond to Williamson's comments.
Former MP David Carter was elected to the board after the 2020 election and sought the presidency – but quit in 2021 when Goodfellow was re-elected president, saying he had "zero confidence" in Goodfellow.
Carter was not commenting but it is understood he had made it clear to the party that he was not prepared to work alongside Goodfellow again.
Williamson also believed Goodfellow should step down altogether rather than stay on the board under a new president. He said it was akin to a chief executive of a company staying on to steer their successor.
"I'm sorry but that doesn't fit with any organisation. When you're gone, you should be well and truly gone. It's like politicians – you're a rooster today and a feather duster tomorrow."
He said he had no interest in the role himself. "Oh no, no, no. I'd rather apply for a job as an explosives expert to disarm bombs on the side of the road in Belfast than that. I've never sought or want to be involved in the party at that level."
The National Party annual general meeting will be held on Saturday August 6.
