Ms Collins - whose husband, David Wong-Tung, is a director of milk exporter Oravida - also paid a visit to the company's Shanghai office, an event the firm used for promotional purposes.
While she has previously acknowledged that she was invited to the Beijing dinner before she left for China, yesterday she confirmed to Parliament that she also knew the border control official would be there and knew his name and position.
Labour MP Grant Robertson said it was beyond belief that Ms Collins thought meeting such a senior official with her husband's fellow directors did not give rise to a conflict of interest.
"John Key needs to reveal whether Judith Collins told him or his chief of staff this was a pre-planned dinner and that she knew the identity of the Chinese official before she left.
"If she didn't, she has surely used up the final warning the Prime Minister gave her," Mr Robertson said.
However, a spokeswoman from Ms Collins' office told the Herald that last week, the minister had given Mr Key's chief of staff, Wayne Eagleson, a full account of the visit, including the fact that she was aware before she left for China that the official would be at the dinner.
Speaking from Beijing, Mr Key said what Ms Collins had told him about the dinner was consistent with what she had said publicly in Parliament. He did not believe there was any further information that had not already been made public.
The month before Ms Collins' trip, Ms Xu said that Oravida was experiencing difficulties getting milk into China after the Fonterra botulism scare and that the New Zealand Government could do more to engage with Chinese officials to help.
However, Ms Collins has denied Oravida's business was discussed during the Beijing dinner.
Asked by NZ First Leader Winston Peters about her comment last week that Oravida wasn't experiencing any difficulties exporting milk to China, given Ms Xu's remarks, Ms Collins said: "What it does show is that I had very little knowledge of Oravida's business, and I should have had more."
Oravida has expanded its interests into gold mining.
Land records show the company spent $3.2 million buying land north of Auckland and on the South Island's West Coast about the time it began exporting milk in bulk to China.
Both chunks of land are used for dairy farming, although the West Coast land also has a prospecting licence registered in the name of Oravida director David Wong-Tung, Justice Minister Judith Collins' husband.
Mr Wong-Tung joined the company as a director in October 2011.
The appointment came around the time Oravida purchased land worth $1.9 million at Kaukapakapa, north of Auckland.
The dairy farm lines up with Oravida's desire to create its own milk supply chain, which dates back to interest in the Crafar farms in 2009.
The West Coast land, which stretches from the township of Ross up the Mikonui Valley, was bought in 2013.
The prospecting permit on it dates from November 2011, is held in Mr Wong-Tung's name, and authorises the company to search for gold, among other minerals.
Local resident Lynley Hargreaves - also an environmental campaigner - said she understood the company's interest was in mining the land and then using part of it for dairy.
Oravida's other commercial interests include swamp kauri products, honey, scampi and salmon.
It also intends to branch into beef, lamb and wine.
