De Jong's 85th-minute header cancelled out Shane Long's opener as the Netherlands fought back to claim a draw against the Boys in Green at the Aviva Stadium on Friday.
The PSV striker was impressed by Long and says that Martin O'Neill's team possess "a good mentality" as well as a dangerous set-piece threat, which will help at the tournament.
"I think they can [cause problems], definitely they can," De Jong told reporters.
"They have a team with a lot of power, with a good mentality always being compact as a team and don’t give away a lot.
"With the free-kicks and corners they are really dangerous so that’s also a weapon in football so I think they can cause problems against the other teams in the Euros."
"Of course Long is a great player up front," noted the former Borussia Monchengladbach forward. "He’s going to be really important for the team.
"What I saw today I think they played really well as a whole team. They want to work for each other and close the gaps in the midfield and the defence.
"That’s really important. It’s hard to get through. You can see we had a lot of problems to get through so I think it’s going to be tough."