Hamer had the better points in pen judging but Oldfield still managed to win the title by almost five points.
The feature of the shearing at the Royal Welsh Show will be Wednesday's test match in which the CP Wool New Zealand team of Nathan Stratford, of Invercargill, and David Buick, of Pongaroa, will be out to bounce-back from defeats at the weekend in the first two matches of a four-test series against Wales.
Team manager Russell Knight, of Apiti, says the Welsh have had the edge with gear selection and the ability to handle the "little" mountain lambs, which he says haven't been the best amid the struggles of a particularly dry summer.
Both Kiwis have, however, proven records in lambshearing in New Zealand, Buick having won the national lambshearing title in Fairlie in April and been runner-up to World champion John Kirkpatrick in the national crossbred lambs championships at Winton in January, a title also won more than once by Stratford.
Results:
Royal Welsh Show Blades final (6 sheep): Allan Oldfield (New Zealand) 13min 33sec, 88.15pts, 1; Clive Hamer (Wales) 16min 36sec, 93.067pts, 2, Rheinalt Hughes (Wales) 18min, 99.167pts, 3, George Mudge (England) 18min 13sec, 103.317pts, 4; Gareth Owen (Wales) 17min 4sec, 103.533pts, 5; Emlyn Roberts (Wales) 18min 3sec, 107.15pts, 6.
Welsh International Speedshear: Jack Fagan (New Zealand) 15.95sec, 1; Gavin Mutch (Scotland) 17.11sec, 2; Richard Jones (Wales) 18.3sec, 3.