A former Finance Minister once forced to bail out BNZ says buying it back would be lunacy. 

New Zealand First is proposed re-nationalising the bank, buying it back from Australia's NAB and merging it with Kiwibank.

Leader Winston Peters says bank profits should remain in New Zealand. 

But Ruth Richardson says the idea has no weight. 

"It makes New Zealand look like a tinpot country, where populist politicians feel free to nationalise private businesses. Why stop at banks? I mean, supermarkets like Woolworths are foreign-owned." 

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