Van Marwijk has come under fire in Holland since the World Cup final, something which Ferguson finds surprising.
The Scot contacted Finland coach Stuart Baxter to pass on his support to Van Marwijk yesterday.
The Dutchman revealed: "Yes, I just spoke with my colleague from Finland. He had to convey the congratulations of Ferguson to me. They called each other Monday.
"According to Ferguson, the Netherlands both in the World Cup qualifying tournament and the World Cup did well. He does not understand the negative mood in the Netherlands. It's nice to hear.''