An Australian artist has started adding his DNA to his paintings to combat forgeries.

　　Pro Hart's paintings have been faked several times and he thinks adding the cells from his cheek will stop the practice.

　　The 73-year-old who lives in Broken Hill, Sydney, is also offering to add the cells to paintings he''s already sold.

　　Mr Hart harvests his DNA by scraping the inside of his mouth with a cotton bud. He sends the cells to a laboratory which processes them.

　　The precise location of the DNA on the painting is added to a database along with other details - the title, size and purchaser - for future identification, the Sydney Morning Herald reports.

　　The artist's son, John Hart, said: "It's about certainty. There's a great demand for his work, so there's always a risk that somebody would want to copy."

　　The DNA coding is not detectable to the naked eye, but if the authenticity of the painting is questioned, scanners can pick it up without disturbing the surface of the work.