Trump was quoted in a UN briefing as asking on Thursday why the United States would accept more immigrants from Haiti and "shithole countries" in Africa rather than places like Norway.
He was speaking while he was rejecting an immigration deal by the two main parties in the US Congress, according to reports.
"These are shocking and shameful," UNHCHR spokesperson Rupert Colville was quoted by Xinhua as saying.
"Sorry but there is no other word that one can use but 'racist'. You cannot dismiss entire countries and continents as 'shitholes' whose entire populations are not white, are therefore not welcome."
Colville said Trump's comments on Norway made the underlying comments very clear.
"This is not just a story about vulgar language, it's about opening the door wider to humanity's worst side, about validating and encouraging racism and xenophobia that will potentially disrupt and destroy the lives of many people," said the UNHCHR spokesperson.
He said that comments made vilifying Mexicans and Muslims, the US policy proposal targeting entire population groups on grounds of nationality or religion, and the reluctance to clearly condemn the anti-Semitic and racist actions of the white supremacists in Charlottesville last year all "go against the universal values the world has been trying to establish since the Holocaust."
In his comments, the UNHCHR spokesperson referred to a speech made by High Commissioner Zeid Ra'ad Al Hussein last year at the Human Rights Council.
In it, he called on the US Congress to provide a durable legal solution for people referred to as the "Dreamers," a group in the United States who lack legal immigrant status.
"The future of the Dreamers should not be used as a bargaining chip to negotiate the most severe and restrictive immigration and security measures possible. These people are human beings, not commodities," said Colville.
He said the UN rights office is very concerned about the decision to terminate the US's Temporally Status Program (TPS) for people from El Salvador (180,000), for Haitians (59,000) and people from Nicaragua (5,300).