Responding to Herald questions yesterday, Mr Barker said he had a "growing frustration at the drip feed from Liu".
"I have decided and advised other media that I am over fishing expeditions. Liu hurls accusations behind cover, protected by others and process," the Hawkes Bay councillor said.
Donhua Liu (second from right) and Rick Barker (right) in China in 2007.
"If he has anything further to say about me, then he is to do so by way of a sworn affidavit. He can afford the legal cost," Mr Barker said. "That way it's open, upfront and should he say things that are untrue he can face the consequences of a legal response."
He also said any further requests for comment should be accompanied by any affidavit signed by Liu.
Sources say Liu paid $15,000 at an auction for a book signed by Helen Clark in 2007. But it is unclear how much Liu paid for the wine and Mr Barker said he presented auction prizes several times at Labour fundraisers.
However, Mr Barker confirmed that the dinner with Liu was on a boat cruise which travelled down the Yangtze River.
"It was a surprise to me when I arrived at the boat. There was no prior indication," Mr Barker said. He was also surprised that staff members from the cement factory he visited earlier were also on the ship. "The front office. The management team. Production workers. Supervisors and technicians. Cleaners and security staff, it felt like everyone from the cement factory and their partners were there. I felt like an intruder on a staff function."
Told of Mr Barker's comments and asked for comment, a representative of Liu said the businessman was "considering his position" but declined to comment further.
Key denies National 'smear campaign' claim by Cunliffe
Prime Minister John Key has denied allegations of a smear campaign against the Labour leader and said it was David Cunliffe's own fault that he was under the spotlight now.
Mr Key was speaking to reporters while in Washington.
He was asked if the Government had set Mr Cunliffe up by knowing about a letter he had written to the Immigration Department 11 years ago regarding Chinese businessman Donghua Liu.
"No David Cunliffe set himself up when he wrote a letter 11 years ago, didn't check his files properly, constantly said he had no knowledge of it then the letter had to be released.
"If the new rules are 'if it is not convenient to release information, we don't have to do' that would be great. I'll look forward to those rules in the future."
Mr Key hinted that more information was yet to come on donations made to the Labour Party by Mr Liu.
"I just think they should go through their records and have a look.
"I'm very confident about that [that there's more]. I hear lots of rumours and lots of gossip around the place. Let's wait and see."
Asked where the rumours had come from he said "it's a highly rumoured Parliament, isn't it".
The Labour Party should expect to live up to the same sort of scrutiny National had been under with its own involvement with Mr Liu, Mr Key said.
"David Cunliffe and Grant Robertson have for the last six months been holding the blow torch to National, expecting accountability of ministers, demanding transparency for the New Zealand public which is fair enough.
