The donation to Mr Ross was made in 2013 and will be listed in his candidate return out today, although Mr Ross has since returned the donation after the election. Mr Cunliffe said it was "dodgy".
"Dodgy because the Prime Minister was "involved, dodgy because a member took $25,000 from Donghua Liu and dodgy because National were trying to frame Labour up while they were on the take."
Mr Cunliffe was blindsided in mid 2014 after claims Mr Liu donated significant sums of money to Labour. That was soon after Labour criticised National's Maurice Williamson for contacting the police to ask about an investigation into Mr Liu, who is now facing domestic violence charges.
Labour was unable to find any record of major donations and no proof has yet emerged beyond Mr Liu's statement that he had donated to both parties.
Mr Cunliffe was also found to have to written a letter to Immigration asking about progress on Mr Liu's case - something Mr Cunliffe said was a stock standard constituent inquiry. At the time Prime Minister John Key had attacked Mr Cunliffe's trustworthiness.
Mr Cunliffe said today that it had damaged his credibility at a critical point of his leadership. "That's because the sensational headlines were run before the facts were established. Although they later fell over, by that stage things were already embedded in the public mind. I think it damaged Labour and I don't think it helped me."
Mr Cunliffe said he believed the National Party was behind it. "I think it's been a very disappointing issue - disappointing that the National Party were clearly telling porkies while they were on the take and secondly, that media swallowed it uncritically."
Mr Ross said the National Party itself had paid for his campaign with about $24,000. That amount was near the cap for candidate spending so he had not needed Mr Liu's donation. Mr Ross denied that he had returned the money because he did not want to be associated with Mr Liu and said he was not embarrassed by it. He had met Mr Liu "more than once, but probably less than a dozen times". He had accepted the donation before he knew about charges of domestic violence Mr Liu is currently facing.
He rejected the suggestion that National had only offered that money to ensure he could return Mr Liu's donation, saying the party had paid for several candidate campaigns. Mr Ross also said the dinner with Mr Key at Mr Liu's home was not a 'Cabinet club' dinner, but the cheque was paid to the Botany Cabinet Club account Mr Ross used for donations. National's Cabinet Clubs are groups of interested members and donors in some electorates, which often arrange fundraisers.
Mr Liu has said he donated equally to "Governments of both colours". "As a private donor I donated to both Governments in good faith and without expectation. It is not my responsibility to make the appropriate political declarations," Liu said in a statement last year.
"Some of these donations were made anonymously which was perfectly legal and so such donations will only ever appear in some individual donation returns as anonymous".
The Labour Party engaged lawyers to challenge Liu's donation claim but did not take the matter further after Liu's lawyer Paul Davison, QC, wrote back to them.
Claire Trevett and Jared Savage of the New Zealand Herald
