O'Connell, who started the RBS Six Nations as Ireland captain until he suffered a knee injury against France, hobbled off in the second half of the RaboDirect PRO12 victory over Ulster on Saturday.
And following initial assessment from the Munster medical staff it has been decided O'Connell now needs to see a specialist - and the fear is that the talismanic lock may have suffered a reoccurrence of the medial ligament damage in his left knee.
O'Connell spent six weeks on the sidelines following the game against France - and if he has aggravated the problem then it would seem highly unlikely that he would make the trip to New Zealand.
Ireland are due to play three Tests against the All Blacks, starting at Eden Park on June 9. Ireland will then take on the World Cup winners in Christchurch seven days later before completing their tour in Hamilton on June 23.
O'Connell is unlikely to play against this season, with Munster claiming the second rower is 'unlikely' to face the Ospreys in the RaboDirect PRO12 play-off semi-final.
Damien Varley (ankle) is also set to miss that match, although Ronan O'Gara and Ian Keatley are set to be passed fit.
Gilbert has released a new line of rugby cleats. The Gilbert Virtuo 8S is part of the exciting new product. Check it out.
The entire All Blacks apparel line has been updated for 2013/14. Check out the New Zealand All Blacks polo.
The Nike Tiempo is a solid rugby cleat and one of few styles still made from full-grain natural leather.
The Gilbert Blitz 8S rugby cleat is a great cleat at a great price of $69.99. Get a new pair of cleats today.
A cool looking all black rugby cleat with the high performance adidas is known for. Get in the Gear!
Wear the crest of the British and Irish Lions on your t-shirt. A great look for the summer.
The All Blacks Performance t-shirt is black with hints of blue from the training jersey. Very Cool.
The New Zealand All Blacks training jersey for 2013/14. Get in the Gear!
The USA Rugby Pro Alternate rugby jersey is perfect for any fan of the Eagles. Get yours to wear during the summer Test matches.
The NEW All Blacks 2013/14 jersey has arrived at World Rugby Shop. Dare to wear the colors of the All Blacks.