The two speakers have let it be known that they want to work quickly, but also be discrete about their contacts.
This morning Messrs Flahaut and Pieters saw the leaders of the Flemish and Francophone green parties, Wouter Van Besien and Jean-Michel.
This afternoon the Flemish and Francophone Christian democrats, Wouter Beke and Joëlle Milquet, were invited.
On Wednesday the speakers see Flemish socialist leader Caroline Gennez. The two key players, Flemish nationalist leader Bart De Wever and Francophone socialist leader Elio Di Rupo are also expected to meet with Messrs Flahaut and Pieters soon.
The speakers have pencilled in three days for such meetings.