The Stormers' suffocating defence squeezed the life out of the NSW Waratahs Super 14 campaign, with a 25-6 semi-final win over in Cape Town on Saturday.

The result set up an all South-African final next weekend in Soweto, where the ladder-leading Bulls gave themselves a shot at a third title in four years with a 39-24 win over the Crusaders in the first semi-final.

Impressive Stormers' centre Juan De Jongh scored the only try of the game in the first half.

Five-eighth Peter Grant converted and kicked six penalties, as South African referee Mark Lawrence punished the undisciplined Waratahs for numerous infringements in the scrums, lineouts and at the breakdown.

Poor discipline apart, NSW were unable to capitalise on the few occasions they did breach the Stormers' renowned defence, especially in the second half, where hooker Tatafu Polota-Nau, centre Tom Carter and winger Drew Mitchell couldn't find teammates near the Stormers' line.

NSW captain Phil Waugh said it was a disappointing effort by his team and that they hadn't taken their chances.

"We broke their line and turned the ball over numerous times," flanker Waugh said.

"In semi-final football you can't do that. Their discipline was good and they kicked penalty goals and kept accumulating points."

The visiting forwards made little ground through the pick and drive, while the in-form back three of fullback Kurtley Beale and wingers Mitchell and Lachie Turner had few opportunities.

Grant kicked two penalties to give the Stormers an early 6-0 lead, but the Waratahs drew level after their pivot Berrick Barnes landed a penalty and a field goal.

NSW paid dearly for fluffing the restart after the field goal, with de Jongh stepping past prop Dan Palmer and Beale and Mitchell for the only five-pointer of a scrappy penalty-riddled affair.

Up 13-6 at the break, the more disciplined Stormers cruised to victory in the second half, with Grant booting four more penalties.

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