Britain is seeking to replicate trade agreements with non-EU countries for when it leaves the EU. If it leaves with a deal, then a transitional period kicks in, keeping current trading arrangements in place until the end of 2020.
"It may not be possible to get all of (the trade deals completed) because some countries don't yet believe that no deal is a possibility," Fox said in an interview with the BBC in Davos.
"No deal is a genuine possibility, and they need to prepare for that, because if they don't prepare, there could be a break, even if it's a temporary one, in the trading relationship that we have on those countries on a preferential basis."
(Reporting by Alistair Smout; editing by Guy Faulconbridge)
