Pope Francis yesterday approved sainthood for Mother Teresa, the missionary nun who became a global if controversial symbol of compassion for her care of the sick and destitute.

The pontiff set September 4 as the date for her canonisation, elevating the Nobel peace laureate to an official icon for the Catholic faith.

The move comes 19 years after the death of the Albanian nun who dedicated much of her adult life to working with the poor in the slums of Kolkata, India.

Teresa took the first step to sainthood in 2003 when she was beatified by Pope John Paul II following the recognition of a claim she had posthumously inspired the 1998 healing of a critically-ill Bengali tribal woman.

Last year she was credited by Vatican experts with inspiring the 2008 recovery of a Brazilian man suffering from multiple brain tumours, thus meeting the Church's standard requirement for sainthood of having been involved in two certifiable miracles.

Teresa, who was 87 when she died in 1997, was revered by Catholics and many others around the world. Known as the "Angel of Mercy" or "Saint of the Gutters", she won the 1979 Nobel peace prize for her work with the poor.