A Japanese government-funded research laboratory has announced that it is considering retracting a research paper describing a simple way of turning ordinary cells from mice into stem cells.

The Riken Center for Development Biology in Kobe, Japan, has been looking into questions raised over images and wording in the paper, co-authored by lab scientist Haruko Obokata.

Riken said Tuesday that it may retract the paper because of credibility and ethics issues, even though an investigation is continuing.

The paper was published in the scientific journal Nature in late January. It was praised as a possible groundbreaking method for growing tissue for treating illnesses such as diabetes and Parkinson's disease using a simple lab treatment.