In a large stock pot brown the pork cubes in batches until well browned. Put to the side and reserve juices.
Add the olive oil to the pan and add the onion and cook until softened and starting to brown, about 5-6 minutes. Add the garlic, carrots and celery, stir to combine. Add the stock base and tomato paste and stir till the vegetables are coated.
Put pork and juices back in the pan and add the water. Add the sprig of rosemary.
Bring to a boil and reduce heat and simmer stirring occasionally for about 2-3 hours.