Peter Sutherland told peers the future prosperity of many EU states depended on them becoming multicultural.
He also suggested the UK government's immigration policy had no basis in international law.
He was being quizzed by the Lords EU home affairs sub-committee which is investigating global migration.
Mr Sutherland, who is non-executive chairman of Goldman Sachs International and a former chairman of oil giant BP, heads the Global Forum on Migration and Development , which brings together representatives of 160 nations to share policy ideas.
He told the House of Lords committee migration was a "crucial dynamic for economic growth" in some EU nations "however difficult it may be to explain this to the citizens of those states".
An ageing or declining native population in countries like Germany or southern EU states was the "key argument and, I hesitate to the use word because people have attacked it, for the development of multicultural states", he added.
"It's impossible to consider that the degree of homogeneity which is implied by the other argument can survive because states have to become more open states, in terms of the people who inhabit them. Just as the United Kingdom has demonstrated."
Mr Sutherland, who has attended meetings of The Bilderberg Group , a top level international networking organisation often criticised for its alleged secrecy, called on EU states to stop targeting "highly skilled" migrants, arguing that "at the most basic level individuals should have a freedom of choice" about whether to come and study or work in another country.
Mr Sutherland also briefed the peers on plans for the Global Migration and Development Forum's next annual conference in Mauritius in November, adding: "The UK has been very constructively engaged in this whole process from the beginning and very supportive of me personally."
Asked afterwards how much the UK had contributed to the forum's running costs in the six years it had been in existence, he said it was a relatively small sum in the region of "tens of thousands".