Ireland (20) 32
Skipper Brian O'Driscoll got over for Ireland's opening try
Tries: O'Driscoll, Trimble, Easterby, penalty try, Flannery
Cons: O'Gara (2)
Namibia (3) 17
Tries: Nieuwenhuis, van Zyl
Cons: Wessels (2)
Ireland secured an expected victory in their opening World Cup match but were far from convincing against Namibia.
Despite a fourth-minute try from Brian O'Driscoll, the Irish only managed two further touchdowns by Andrew Trimble and Simon Easterby before half-time.
Ireland were awarded a penalty try early in the second half but were hit by Namibian tries scored by Jacques Nieuwenhuis and Piet van Zyl.
Replacement hooker Jerry Flannery got over for a late try for Ireland.
Coach Eddie O'Sullivan is bound to be concerned about Ireland's scrappy display and the number of passes which failed to go to hand.
They have a lot to work on before facing Georgia on Saturday.
It had all started so promisingly when O'Driscoll chipped ahead, ran onto his kick and shrugged off Ryan Witbooi to score his 30th Test try.
O'Gara converted and then landed a penalty in the 17th minute to ease Ireland into a 10-0 lead.
Andrew Trimble gathered O'Gara's kick top score a try
The fly-half set-up Ireland's second try on 29 minutes by taking a tap penalty and kicking to the right corner where winger Trimble gathered before touching down.
Namibia fly-half Emile Wessels landed a long-range penalty on the stroke of half-time.
Four minutes into the second half referee Joel Jutge responded to two collapsed scrums by awarding Ireland a penalty try and the Namibians could have few complaints.
The score secured a bonus point but the Irish were struggling to put Namibia away.
Heading into the final quarter, it was the Africans who were playing with greater conviction big blindside forward Nieuwenhuis thundered over for a 61st-minute try.
The Bordeaux crowd were roaring with approval as van Zyl quickly added another touchdown.
Ireland got the final score when Flannery seemed fortunate to be credited with a try in the left corner.
Ireland: G Dempsey: A Trimble, B O'Driscoll, capt, G D'Arcy, D Hickie; R O'Gara, P Stringer; M Horan, R Best, J Hayes, D O'Callaghan, P O'Connell, S Easterby, D Leamy, D Wallace.
Replacements: J Flannery, N Best, M O'Kelly, S Best, I Boss, P Wallace, G Murphy.
Namibia: T Losper; R Witbooi, B Langenhoven, P van Zyl, H Bock; E Wessels, E Jantjies; K Lensing (captain), H Horn, J du Toit, W Kazombiaze, N Esterhuize, J Nieuwenhuis, H Senekal, J Burger.
Replacements: J Meyer, J Redelinghuys, M MacKenzie, T du Plessis, J van Tonder, LW Botes, M Africa.