The Dutch secured their berth at next June’s tournament in Germany by beating Ireland 1-0 in Amsterdam on Saturday to secure second place in Group B and now complete their schedule in Faro, Portugal.
"I want to see some new guys in action," Koeman told a press conference on Monday, adding that despite the busy schedule of his top players no one was voluntarily giving up their spot.
"They all want to have as many caps to their name as possible, so they are not happy if I don't field them."
The Dutch are up against a Gibraltar side reeling after a record 14-0 loss to France in Nice on Saturday and Koeman said his side would be looking for lots of goals, too.
"You have little to gain in a match like this. We see it as a preparation for the European Championship. Against this opponent you want to see intensity and many goals," Koeman added.
"I'm not really concerned with a record victory. I want to feel afterwards that we have done everything we can to score goals. It seems clear to me that the attacking game will have to be better than it was against Ireland."
Wout Weghorst scored early in Saturday's game against the Irish but despite plenty of possession and chances, the Dutch were unable to add more goals.
Koeman also let slip in the press conference that the Dutch have arranged a friendly against Germany next year but said it would be cancelled if the two sides were drawn in the same group for Euro 2024.
The draw is in Hamburg on December 2nd.
