"In five years there will still be 28 member states," Schelling told German business daily Handelsblatt.
European leaders were discussing "all possibilities" -- from Britain remaining in the EU to sealing "a free trade agreement on the Swiss or Norwegian model", the former businessman said.
Schelling said that the United Kingdom could break up, with Scotland and Northern Ireland -- where the majority of the electorate voted to stay -- remaining members of the EU while pro-Brexit England goes its own way.
In the historic vote, 52 percent of Britons voted to leave the EU and 48 percent voted to remain. The country has since been plunged into political turmoil.
Prime Minister David Cameron -- who led the 'Remain' campaign -- has resigned and top figures in the 'Leave' campaign have also stepped down. A leadership battle has also broken out in the opposition Labour party.
Some fellow EU members have pushed Britain to trigger exit proceedings immediately to ward off economic uncertainty, but there is no legal requirement for the government to do so.