It was the second easy win against a top player on Rosmalen's grass courts for the in-form Romanian, after she outclassed top-seeded Roberta Vinci 6-0, 6-1 on Wednesday.
Last Saturday, Halep won her first WTA title by beating Andrea Petkovic of Germany on clay in the final of the inaugural Nurnberger Versicherungscup.
Fourth-seeded Flipkens of Belgium beat Garbine Muguruza of Spain 6-3, 6-1 in the other semifinal.
Results from the fifth day of the WTA 's-Hertogenbosch International (x denotes seeding):
Women:
Semi-final:
Simona Halep (ROM) bt Carla Surez (ESP x3) 6-3, 6-2
Kirsten Flipkens (BEL x4) bt Garbie Muguruza (ESP) 6-3, 6-1