The two pools were confirmed on Monday after New Zealand accepted an invitation to play in Brazil.
The Dutch are ranked number two in the world with Germany third, while Ireland will also take on Argentina, India and Canada in Pool B.
"We're know how tough the tournament is and that we're in a tough group," said Irish coach Craig Fulton.
Argentina (sixth) and India (seventh) are above Ireland (12th) in the rankings with Canada 14th.
Pool A comprises Australia, Great Britain, Belgium, New Zealand, Spain and host Brazil.
"We will be focusing on improving as individuals, and as a squad and team come Rio," added Fulton.
"Our first training camp is in early January and we're looking forward to starting 2016 with a tough but enjoyable tour."
The match schedule for all pool games and the play-off stages will be announced in February.
Ireland's pool opponents at the Rio Olympics will include defending champions Germany and the Netherlands.