The leaders of Germany, France and Italy will meet on Monday to discuss how to keep the European project together, in the second set of talks between the coutries since Britain's shocking vote to leave the bloc.

Italian Prime Minister Matteo Renzi said on Sunday that they will discuss how to relaunch Europe from the bottom up.

Officials in Brussels and Berlin fear the June 23 vote could lead to a referendum in the Netherlands - a founding member of the union - on whether to also leave the bloc.

Faced with existential risks, Merkel wants to cement "a better Europe" rather than forge ahead with "more Europe".

Renzi wants Italy to have a strong voice in how the bloc's future is shaped after Brexit and, according to the French diplomatic source, Hollande wants an EU-wide investment plan to be doubled.