The Greens co-leader accuses Reserve Bank governor Graeme Wheeler of misleading Parliament over the profitability of New Zealand banks, and of being the banks' champion when he is also their regulator.
The banks themselves Norman accuses of "strip mining" the economy, making super profits for their Australian owners.
The first of these accusations is arguably a fair cop, in a pedantic sort of way. The rest are wide of the mark.
If any bias has been on display it is Norman's against the banks, commercial and central. In someone who evidently aspires to be Finance Minister it is a troubling spectacle.
The story began a month ago when Wheeler appeared before Parliament's finance and expenditure select committee to be quizzed on the Reserve Bank's financial stability report.
Winston Peters asked him about the banks' profits and the flow of dividends offshore.
"If you look at return on assets in New Zealand it has recovered to where it was prior to the global financial crisis. If you compare it to the return on assets across most OECD economies we are in fact about average or below," Wheeler said.
"If you look at the return on equity we haven't got back to where we were prior to the global financial crisis and that is partly because the banks are building up capital as part of the Basel III requirements and Reserve Bank's requirements."
The problem is that about half the members of the OECD are also in the eurozone, mired in recession and an apparently endless debt crisis which takes a toll on their banks' profitability.
Looking at the non-eurozone advanced economies, if you rank New Zealand among the 13 who report return on assets (RoA) on a before tax and extraordinaries basis, we are fourth from the top, between Australia and Canada.
Compared with another three who report on a post-tax and extraordinaries basis, New Zealand banks have a lower RoA than the Czech Republic and Israel, but higher (thankfully) than the United Kingdom.
Analysis of returns on equity tells a similar story.
Releasing the information this week Wheeler said the analysis had not been complete at the time of the select committee hearing and his response had represented his understanding at the time.
So okay, not strictly accurate, but give the guy a break, he has only just started the job.
Hardly grounds for implying bias.
The other thing is that the Reserve Bank data aggregates banks' returns over the three years 2009 to 2011.
You would expect the profitability of many northern hemisphere banks to have taken a hit from the global financial crisis, especially in its immediate aftermath.
Data from the Bank for International Settlements, helpfully supplied by the Greens, illustrates that point.
The big four Australian banks' pretax return on assets rose from 0.93 per cent in 2009 to 1.19 per cent in 2011.
The biggest nine United States banks, by contrast, went from an RoA of 0.36 per cent in 2009 to 0.93 per cent in 2011.
Britain's big six went from 0.18 per cent in 2009 to 0.33 per cent in 2011.
The big four New Zealand banks averaged just over 1 per cent over that period.
As Norman tells it, that shows the local banks are "strip-mining the economy", making profits that are way above average and sending them offshore.
"No one wants bankrupt banks but if they were doing averagely well that would be great. To say that the banks have to be the most profitable on the entire planet to be successful is going a bit far," he said on Radio NZ.
No one, of course, is saying that.
We should be relieved, even grateful, to have avoided the kind of financial crises which engulfed the United States and Europe in 2008.
We should not be surprised that our banks' profitability puts us in company of countries, like Australia and Canada, which also avoided the need for massive bank bailouts to avert systemic failure.
Even if that means returns that are higher than an average diluted by countries which were not so lucky - or not so well regulated.
David Tripe, who heads Massey University's Centre for Banking Studies, says the New Zealand banks' pretax RoA of just over 1 per cent is "actually quite low profitability" and the after-tax measure of 0.6 per cent is "certainly not outrageously high, either historically or internationally".
"Temporarily banks' returns internationally are somewhat lower than that but that is as much as anything a reflection of issues around the global financial crisis, and the European banks are suffering ongoing losses as a result of exposure to Greece and the like."
To be fair, a couple of legitimate concerns lie behind Norman's bank-bashing.
One is the risk of a housing bubble inflating in Auckland.
How the Reserve Bank sees that risk we will hear this morning.
But it is certainly unfair for Norman to say that the governor "is very clear he will not be intervening to stop that bubble".
Or that the banks will heedlessly inflate it: "They make money out of lending, right, so they love the fact that housing asset bubbles develop because they make a lot of money out of it ... What we want is a regulator to put some restraints on the banks' understandable desire to throw lots of money into the housing sector and that's why we need an independent regulator who is willing to stand up to the banks."
The case for tougher regulation of banks has been emphatically made by the GFC, and the Reserve Bank like other regulators is equipping itself with additional tools to do that.
All that Wheeler has said is that so far he does not see indicators, like rapidly accelerating credit growth, that would warrant employing them.
When bubbles burst, banks' shareholders are among those who pay the price, so it is a bit swift to assume that they have every incentive to create one.
The other legitimate concern is the country's current account deficit, to which the banks' multi-billion-dollar profits are a major contributor.
But having sold the Bank of New Zealand, ASB, Trust Bank and so on to the Australians we cannot now complain.
And what the Greens, and Labour for that matter, ignore is that the current account balance is also the difference between investment and savings.
They advocate a regime in which the Reserve Bank is instructed not to worry so much about inflation but to keep nominal interest rates low in the hope - and it can be no more than a hope - that that will lower the exchange rate and provide relief for the tradables sector.
But an environment in which the real interest rates depositors get are low is going to discourage savings and make the current account deficit wider, not narrower.
And it will increase the incentive to borrow and invest in real estate.
From the standpoint of the left's declared objectives, it would be a total own goal.