Goldman Sachs Group's Chief Executive Lloyd Blankfein has become the first major Wall Street leader to speak out against President Donald Trump's so-called "Muslim ban".

The executive order barring travel to the US from seven Muslim-majority countries is expected to cause havoc among businesses and universities, and has drawn criticism from a number of organisations.

But the criticism from Goldman is unexpected due to the bank's perceived closeness to Trump, who has hired six people from the organisation into his inner circle.

"This is not a policy we support, and I would note that it has already been challenged in federal court, and some of the order has been enjoined at least temporarily," Blankfein said, according to a transcript of an internal memo seen by Reuters.

Blankfein's comments were also unexpected due to the perceived lack of criticism of Trump's executive order from other leading Wall Street establishments.

According to Reuters, top BlackRock executives sent a memo to staff on Monday (30 January) saying Trump's order presented "challenges" to its goals of diversity and inclusion.

"We, of course, all want to promote security and combat terrorism, but we believe it needs to be done with respect for due process, individual rights and the principle of inclusion," the memo said.

Citigroup CEO Mike Corbat said in a memo the bank is concerned about "the message the executive order sends" as well as the impact immigration policies might have "on our ability to serve our clients and contribute to growth".

JPMorgan Chase failed to criticise the order, but said the country was "strengthened by the rich diversity of the world around us."

A Bank of America statement said: "We depend upon the diverse sources of talent that our teammates represent."

Banks such as Morgan Stanley and Wells Fargo said they were monitoring the situation closely, whereas all other remaining Wall Street banks failed to comment.