The Stormers have a long history of blowing hot and cold and this season have again struggled for consistency, mixing 50-point romps with low-scoring defeats.

The South Africans have yet to put back-to-back wins together in 2009, but star winger Lote Tuqiri said the second-placed Waratahs would be foolish to underestimate their ninth-placed rivals.

''You never know what you're going to get with them. It depends on how they're feeling,'' Tuqiri said.

''They're a bit like the [Auckland] Blues as well at times they can come out and put 40 or 50 on you. But over the last few years our games have been close.''

In a star-studded backline, Tuqiri nominated midfielder Jean De Villiers as the key for the Stormers.

''He's probably one of the premier centres in the world. So he'll have to be watched,'' Tuqiri said.

Waratahs coach Chris Hickey agreed that the Stormers' fluctuating form made them a challenging proposition.

''Sometimes teams that are less consistent can be harder to prepare for,'' he said.

''If you look at their team, they've got plenty of Springboks in there and plenty of players who can play really well. It will depend on how they handle this Australasian leg of their tour.''

Injured scrumhalf Luke Burgess was unable to train with the Waratahs yesterday but he is expected to be fit to play against the Stormers.

''He's still got a fairly severe cork,'' Hickey said. AAP