Dotcom claims the donations were discussed when Mr Banks visited him shortly before it was paid into his campaign account. But Mr Banks said yesterday he did not know the donations had been made until proof was reported by the media late yesterday.
He told reporters he had received legal advice that his campaign finance declarations were within the law but that he should not comment on them so as not to jeopardise a possible inquiry. "That piece of advice, while I respect it, in hindsight, I regret taking."
Had he ignored that advice he would have answered questions about the donations over the past five days "quite specifically and quite easily".
"Then I wouldn't find myself in this situation where people think I'm obfuscating."
But Mr Banks denied misleading the public about the donations and events around them, including a helicopter ride to Dotcom's mansion which he has said he cannot remember.
"I didn't lie. There's no reason to believe that I lied. I simply couldn't recall."
He said he welcomed the police inquiry into the matter as he had nothing to hide. Mr Banks did remember that he might have called Mr Williamson about Dotcom's OIO application more than once, but that was not in itself improper.
"I wasn't mayor of Auckland, I wasn't a member of Parliament, I was a private citizen. I made the phone call and I'd do it again," Mr Banks said.
"Of course, subsequently the Government didn't take my high-level political lobbying and turned him down."
He advocated on behalf of Dotcom because he had sympathy for him.
"One, because he had been particularly generous to New Zealand; two, he was an entrepreneur who came to New Zealand to live in this home and do great things for New Zealand; three, he was a New Zealand resident; and four, I could see no reason a New Zealand resident ... shouldn't be able to buy property here."
Mr Banks' minor portfolios made it difficult for the Opposition to tackle him on the Dotcom affair yesterday.
Instead, Labour Leader David Shearer, his deputy Grant Robertson, NZ First's Winston Peters and the Greens' Metiria Turei directed their attacks at Prime Minister John Key and Mr Williamson. However, Mr Key said that as Mr Banks had assured him he had complied with the law around campaign donations, "he continues to enjoy my confidence".