The statements were provided in 2009 when Auckland police officers went to China.
They are on the Auckland High Court file but the witnesses did not come to New Zealand to testify.
Prosecutor David Johnstone said that as Mr Yan's trial date drew nearer, "it became apparent the Chinese authorities were not making meaningful arrangements for witnesses to travel to New Zealand to give their evidence".
"The Crown had no choice but to confine its case to the documents offered to Australian and New Zealand immigration on behalf of Mr Yan."
The reason for the lack of action on China's part remains unclear, Mr Johnstone said.
Mr Yan was last month acquitted of five charges of making false statements on immigration and citizenship documents.
Justice Timothy Brewer said the evidence put before him "proves a situation that is highly suspicious".
Most of the documents were false but were filled out by others on Mr Yan's behalf.
"In the absence of firm evidence that the accused knew of the falsity ... there would need to be proof of dishonest intention in using the Liu Yang identity," the judge said.
"Such proof, of course, would have to come from admissible evidence.
"The Crown has not been able to put such evidence before me."
Mr Yan has said his different identities and birth dates are valid and came about because he was fostered out by his birth parents in China and both sets of parents registered him as part of their household with different names and dates of birth.
A Crown summary of the evidence of the witnesses in China alleges his multiple identities arose from him "developing close relationships with senior political figures in Jilin Province ... China" and promising to invest heavily in the area.
Witness statements included:
Feng Gao, who said he was director of the Public Security Bureau in Tonghua County in 1999 when he was approached by "a standing deputy governor" of the county's government. As a result he assigned two policemen to provide protection to Mr Yan "who had apparently had some sort of business dispute".
Mr Gao said he was given to understand that Mr Yan "was supposedly about to invest heavily in Tonghua County".
He put his deputy, Shi Teng, in charge of providing security for Mr Yan.
Shi Teng said he facilitated the creation of a false ID card in the name of Yang Liu and claimed Mr Yan also asked him if it was possible to change the date of birth from 1971 to 1969 on his identity document in his real name of Yongming Yan.
"I knew [Mr Yan] had very good relationships with both county and municipal leaders and it would be very easy for him to make this happen anyway."
Xiu Hai Jia, Teng's boss, said that as a result of his part in the deception he was given a three-year suspended jail sentence and dismissed from his job as director of public security. Mr Jia said he directed a staff member to create a false identity document.
"The name I told him to write was Liu Yang, and the date of birth was 20 October 1972. The ID card number was comprised of this date of birth and the code of the Xinglin Township Police Substation Precinct, which I was director of."
"In fact, there was no real person with those particulars in my precinct at all, and the document is completely false."
Had the Chinese witnesses been called to testify, Mr Yan's defence planned to call evidence that oral and documentary evidence given in China was unreliable.
In a submission in 2008 in support of Mr Yan's application to be granted citizenship, John Billington, QC, said there were no false passports and his client had used both identities in China.
He accused New Zealand officials of taking a subjective view on unproven allegations.
Mr Yan's insistence that he is one man with two legitimate identities is at odds with a letter written on his behalf in January 2001 to Australian authorities that purports that Yongming Yan and Yang Liu are two different people.
The letter, an exhibit in the recent court case, was in support of a business visa application by Yang Liu and was written by an agent with whom Mr Yan was closely associated.
It said Yongming Yan was general manager of Tonghua Golden Horse Pharmaceutical Ltd and had decided to set up a sales office in Sydney.
"His assistant Mr Liu has been assigned to Australia to finilise [sic] the task."
During the trial, New Zealand Internal Affairs case officer Johannes Gambo alleged that Mr Yan had admitted that he used two identities because he didn't want Australian immigration officials to "know that I've been there".
Unheard evidence
* Mr Yan was last month found not guilty of making false statements on immigration and citizenship documents. Justice Timothy Brewer said the circumstances were "highly suspicious" but there was no admissible evidence to prove Mr Yan had dishonest intentions.
* Witness statements prepared for the case by Chinese officials had alleged Mr Yan obtained false identity documents through corruption to gain New Zealand citizenship.
* But the claims were never tested in court because the witnesses did not come to New Zealand to give their evidence. The defence planned to argue the officials' claims were unreliable.
* The case has been controversial because when Labour MP Shane Jones was a Cabinet minister, he granted Mr Yan citizenship in 2008, against the advice of officials, who said he had not met good character requirements.
* The Auditor-General this week appointed Francis Cooke, QC, to conduct an inquiry into Mr Jones' decision and the circumstances surrounding it.
