An investigation by the University of Hong Kong (HKU) has affirmed that a paper by a PhD student contained non-existent references generated by artificial intelligence.

The findings, announced by the university on Wednesday, also prompted the corresponding author of the publication, Professor Paul Yip, to step down as associate dean of the faculty of social sciences.

The paper is titled "Forty years of fertility transition in Hong Kong" and published in the "China Population and Development Studies" journal in October.

According to the journal, the article was retracted on Monday.

"The university's investigation substantiated that certain citations of the paper included non-existent publications generated by AI, which had not been disclosed by a PhD student involved in the research," HKU said in a statement.

"The university has administered disciplinary actions and appropriate measures, including that the corresponding author has stepped down from his associate deanship at the faculty and also membership from research committees of the faculty and the university.

"The corresponding author has also requested for retracting the paper from the relevant journal.

"The PhD student involved is also subject to the university's disciplinary procedures."

Following the incident, HKU vowed to strengthen mandatory training and assessment for all researchers in areas such as the use of artificial intelligence in academic research "for ensuring academic integrity is observed".

All researchers are required to make sure their work meets international recognised benchmarks for quality and ethical conduct, the university added.