Labour MP Willie Jackson has fiercely defended labelling the Tax Working Group chair's $1000-a-day pay "peanuts".
"$1000 a day for a man of that experience and that background and this type of responsibility is not a huge amount," the Employment Minister told Magic Talk on Thursday.
"This guy's not driving a truck, this guy's not working at the factory; he's actually trying to adjust life as we know it."
The Labour list MP was referring to the proposed changes in the Tax Working Group's (TWG's) February report, which includes a proposed capital gains tax.
The decision to extend the contract of TWG chair Sir Michael Cullen has been controversial. Last week Finance Minister Grant Robertson was forced to defend the move, after National and ACT said he should have taken over from Sir Michael.
"The Tax Working Group has delivered its report. It's now up to the Government to respond and publicly defend its plan for our tax system," ACT leader David Seymour said last week.
Seymour suggested the extension of Sir Michael's appointment as the chair of the TWG was a "vote of no confidence in the ability of Finance Minister Grant Robertson to articulate and defend his Government's tax plan".
Sir Michael, a former Finance Minister, will be paid $1062 a day or $177 an hour for a minimum of six hours a day in his role. However, it has not been disclosed exactly how much work he will charge the Government for.
On Wednesday, Jackson said in Parliament that Sir Michael's $1000-a-day pay was "peanuts, actually, when you compare it to some of the lawyers who've worked in this Government in the past".
"He's under-charged himself, there's no doubt about that."
He defended those comments on Thursday, telling Magic Talk: "Let's not underestimate what his job is - he's not your average person out there. Taxpayers' money can be used reasonably."
Jackson clashed with Magic Talk host Sean Plunket, who argued it wouldn't be fair to expect taxpayers to foot the bill for an increase in Sir Michael's pay when $1000-a-day is a lot compared to what some people earn.
But Jackson said some law firms charge $600-$700 an hour, and given Sir Michael's knowledge and experience on tax, he should be paid accordingly.
"This is responsible work," he said.
The issue was raised in Parliament on Thursday, with National's finance spokesperson Amy Adams questioning the Finance Minister about the legitimacy of Sir Michael's extended role and his $1000-a-day pay.
Adams asked Robertson why Sir Michael is being paid with "taxpayer funds to do and I quote, 'favours', for the Government, as Willie Jackson stated in Parliament yesterday".
Robertson said Adams' comments were an unfair "characterisation" of what Jackson said. He told Parliament Sir Michael is needed to "explain the recommendations of the [TWG] while the matter is under consideration by the Government."
He said Sir Michael's pay is based on Group 4 Level 1 under the Cabinet Fees Framework. A Treasury document shows that the chair was paid a daily rate of $1,062, and members were paid a daily rate of $800.
Last week Robertson said he felt it was reasonable to keep Sir Michael on, considering he thought there had been "misrepresentations" about the TWG's report, and that he would "respond to that appropriately".