The following are known Action Replay Codes for Shrek: Reekin’ Havoc on Nintendo Game Boy Advance (GBA).
These codes were also known as GameShark Codes and in most cases will work on both devices.

These codes are for the U.S. version of the game.

Master Code – Must Be On
b8c0051c
8b405aa1
8ee335cb
e1a474dd

Max Leaves Bar
dcec9586
9d36f90a

Infinite Leaves
95af32c2
cd4ff28c

Max Health Bar
ed2823c8
23a2ef98

Infinite Health
26feee07
ec62f0b1

99 Lives
00d0e931
f1218694

Start with Max Char
f98d2dc7
5419b141

Max End Lvl Pts
4085008a
595b52b1
eb5583c2
72a8b8df
faff7f9b
91427306

Always A Ranking
6294438f
b20ce55c

Enable Level Select
f6a584ea
6892d9d4

Free All Hostages
5a001be9
809fffb8

Always Bat Slash
5e106a30
511e2013

Always Sword Slash
a95267f0
51d1afe5

Play as Shrek
971b8468
7e57ddd0

Play as Fiona
398b1439
bd36e2b0