"We've seen how dynamic a batsmen he is and can threaten any bowling attack in the world. It'll be great to have him back in the mix."
Elliott returns after fracturing a wrist in November during Wellington
training.
''He brings a lot to the squad and obviously has experience in pressure moments, which is key to batting in the middle order in T20."
Swing bowler Trent Boult will return for the final ODI against Sri Lanka, while George Worker drops out for the last two games.
New Zealand ODI squad for the last two games against Sri Lanka:
Brendon McCullum (c), Martin Guptill, Tom Latham, Kane Williamson, Ross Taylor, Henry Nicholls, Mitchell Santner, Luke Ronchi, Doug Bracewell, Ish Sodhi, Tim Southee, Adam Milne, Mitch McClenaghan, Trent Boult (fifth game only).
New Zealand T20 squad:
Williamson (c), Guptill, Ronchi, Taylor, Colin Munro, Grant Elliott, Corey Anderson, Santner, Southee, Sodhi, Milne, McClenaghan, Boult.