Alan Colman, the CEO of ES Cell International, said: "It is the first time lines have been made according to the current good manufacturing practice conditions."

The new cell lines have not been made with any living animal tissue and so are believed to be safe for clinical use in humans.

Colman said: "Most of the lines existing already, and certainly the ones available in the United States, have been in contact with mouse cells. This condemns them ... if they ever get to be used in clinics. It imposes extra burdens on the nature of the clinical trial."

They have produced and stored six new cell lines suitable for use in clinical trials and expect to store another two in the next five weeks.

He said the lines would be available to researchers worldwide by the end of the year.

Cost

Colman said his company had never before attempted to adhere to the strict guidelines because of the prohibitive cost.

The new cell lines were prepared at a cost of several million dollars, partially subsidised by the juvenile diabetes research foundation international.

He said the research-grade cell lines would be distributed on a non-profit basis to researchers worldwide, while the clinical-grade lines would be made available at a higher cost.

Colman told channel news Asia that he hoped the lines would be used to combat diabetes and heart failure.

"In both cases, we need these new cells to move to the clinic. We've got considerable progress already but that is using existing lines, which are not suitable for going to the clinic. Entry to the clinic means being allowed to be used on humans, to actually use humans in clinical trials."

International debate

The announcement comes a week after George Bush, the US president, vetoed federal funding for embryonic stem cell research in the US.

The European Union voted last week to continue funding embryonic human stem cell research until 2013, but only under new rules that prevent human cloning and destroying embryos.