The first request by British scientists to clone human embryos has been considered by the Human Fertilisation and Embryology Authority.
If the Newcastle researchers' bid is successful, they will investigate using stem cells from the cloned embryos to treat diabetes.
It could open a new era of research by scientists looking for remedies for diseases which are currently incurable.
But other scientists believe therapeutic cloning is unethical.
Experts from the HFEA have already inspected the laboratories at the International Centre for Life in
Newcastle, where the work would take place under the proposal.
Their decision on whether to allow the work is expected early next week.
The Stem Cell Group, led by Dr Miodrag Stojkovic, from the Institute
of Human Genetics at Newcastle University, and Professor Alison Murdoch, from
the Newcastle Fertility Centre, plan to use the same technique that was used to create Dolly the cloned sheep.
Therapeutic cloning has been legal in Britain since 2002.
It involves cloning embryos and harvesting stem cells from them. The embryos are destroyed before they are 14 days old and never allowed to develop beyond a cluster of cells the size of a pinhead.
If the Newcastle research is allowed to proceed, it is likely to be welcomed by many doctors, who hope cloned cells may one day be used to treat conditions ranging from strokes and spinal cord injuries to Alzheimer's and motor neurone disease.
Professor Murdoch told BBC Radio 4's Today programme the research was one of the "most exciting areas of medical development in many years".
She claimed that although the science was similar to reproductive cloning, the aims were completely different.
"We are trying to create material that would be genetically identical to the person who needs treatment.
Stem cells would be used to treat diabetic patients
"If you have a 10-year-old child who has diabetes in Newcastle now, the likelihood is he is going to have to take insulin for the rest of his life.
"Maybe in 10 years' time when we can get these technologies working, we can take a skin cell from him to make some cells which will actually make insulin for that boy.
"We can't take an embryo or any cells from anybody else and make insulin for him because if they were put back into him they would be rejected," she said.
Alastair Kent, from the Genetics Interest Group - which represents 130 charities working for families living with a genetic condition, said millions could potentially be helped by the results of this research.
He rejected concerns about using embryos for research, saying: "It is a matter of balancing the rights and needs of those people who are alive now with a very remote potential future person.
"If we don't do the research, and it does have the potential, then we are not only ignoring the needs of those who are alive now, but also all future generations as well."
But the research would prove controversial, with protests expected from religious and anti-abortion groups and by those who fear allowing therapeutic
cloning could pave the way to allowing the creation of cloned babies.
Dr David King, molecular biologist and director of anti-cloning pressure group Human Genetics Alert, along with six other scientists and ethical experts has written
to HFEA chairwoman Suzi Leather asking her to reject the application.
The planned research is irresponsible,
unethical, scientifically weak, unnecessary and politically motivated, they say.
Dr King said: "This research is a waste of public money, and crosses
important ethical lines for the first time.
"It is very unlikely to produce anything medically useful, but will be a
great help for those who want to clone babies."
The world's first cloned human embryos were created by scientists in South Korea in February and a similar experiment has also been conducted in the US.
Cloning human embryos for therapeutic purposes was made legal by an amendment to the Human Embryology Act in January 2001.
But cloning humans for reproductive purposes remains illegal and is punishable by a 10-year prison sentence and unlimited fines.