Should Collins lose her ministerial portfolios?

The Cabinet Manual contains quite clear guidelines for ministers on conflicts of interest. It clearly spells out that ministerial status or privileges should not be used – or should not even appear to be used – in the furtherance of the private interests of ministers' family or friends. That would have been obvious even if it were not written down in the Manual. Public perception of a conflict of interest can be as important as any material preferential treatment or insider dealing.
Judith Collins is now in a position where, partly due to her own handling of the Oravida scandal, the public perception of, and reporters' questions about, a conflict of interest have gotten out of her control. While the Prime Minister, on Radio NZ this morning, was saying he still has confidence in her as a minister, he said that the Cabinet Office has advised that Collins did allow a perception of conflict of interest to arise. The PM would not answer the question of how he would rate her handling of the affair, and tried to deflect the blame onto Labour for persisting with the issue just to play politics. That leaves me with the impression that he does not rate her handling of the affair very highly.
So, the PM admits that the perception of a conflict of interest was created by the minister. And this alone is contrary to the standards laid down in the Cabinet Manual. Now, the Manual is not law, but it does set out the accepted understandings of cabinet conventions and ministerial conduct. Ms Collins' behaviour has not maintained those standards, and it would be prudent for her to stand down from cabinet at least for the time being while the scandal resolves itself, and possibly until after the election.
There are two obvious reasons why Ms Collins was not 'gone by lunchtime': the PM would not want to buy an internal fight over her removal from office; and the PM would not want to allow the Opposition to claim the scalp of a senior minister. I wonder if another reason is that the PM had miscalculated that the matter would have died down by now.
The PM is right that Labour will play this tune ad nauseam for political reasons; but equally his refusal to remove the minister from office is for political reasons. Mr Key is saying that he has confidence in Ms Collins, but the fact that he even has to say that just shows us that this affair is causing damage. 
If this scandal is still making the political news by early May, then it will begin to interfere with pre-Budget announcements, and potentially with Budget day itself (15 May). That's the political risk that the PM now has to reckon with. Does this story have the legs to run for that long?