Football Federation Australia (FFA) on Thursday appointed van Marwijk on a short-term deal as the man to lead Australia to this year's World Cup following a two-month search for Ange Postecoglu's successor.
With the Dutchman's contract expiring after Russia, Sydney FC coach Arnold is the hot favourite to take over long-term.
Van Marwijk has previously led Netherlands to the 2010 World Cup final, and was recently in charge of Saudi Arabia, who beat the Socceroos to second place in the Asian qualifying group.
"Bert is a fantastic appointment," Arnold said on Thursday.
"It's an appointment that comes with a lot of World Cup knowledge, making the final with the Dutch side, qualifying with Saudi Arabia.
"But also knowing the Australian team inside out from playing against us twice in this campaign. When you do your homework as a coach, you don't just watch one game before.
"You're watching 4-5 games before you actually play them. So no doubt his knowledge is very high on our team and I think it's a great appointment.
“If it wasn’t anyone outside of Bert it would’ve been much tougher."
He said van Marwijk would be aided by the capable Socceroos coaching team.
"Let's not forget we've got a great staff that was in and around Ange Postecoglou and those staff are still there except for one," Arnold said.
"Ante Milicic who served so well alongside Ange for 20-odd games for four years will have huge intel for Bert. So the knowledge will be high and as I said, it's a great appointment."
Arnold was among the potential candidates for the Socceroos position, however ruled himself out of coaching at this year's World Cup on Monday so he could complete the season with Sydney FC.
Questions remain on who will coach the national team after Russia, with Arnold only guaranteeing his post at the Sky Blues until the end of the current A-League season.
He has one season remaining on his current deal after signing a two-year extension last year, and re-iterated his desire to one day hold the national post.
"That's when they'll go through another process ... of course I'm a very proud Australian and I do feel that it's a job that any coach would strive to do and I'm no different to that," he said.
The Sky Blues mentor confirmed the FFA had had no further contact with him about what would happen post-Russia, but reiterated that he was in demand and would be considering several offers.
“Since the last time I had contact with them I haven’t had contact with them anymore," he said.
“I made my intentions clear that I wanted to stay at Sydney FC until the end of this season
"What happens after that happens after that. It’s not just FFA, I’ve had offers from all around the world, and I’ve knocked a few back in the last week and there’s plenty of things to think about.”
