A fake dollar bill with US Republican presidential candidate Donald Trump's picture on it is displayed for sale with other electoral items at a roadside stall as pedestrians walk past in New York.

U.S. President Donald Trump needs to be clearer about his fiscal policies so one can better understand what may happen to the U.S. dollar, a currencies strategist told CNBC on Wednesday.

"I think the dollar is already coming off its post-Trump honeymoon period," Jane Foley, head of forex strategy at Rabobank, told CNBC.