Bulls coach Frans Ludeke says they expect a tough challenge this weekend against the Jake White's Brumbies who will be looking for their first win at Loftus Versfeld since 2006.

The Bulls square up against the Australian conference leaders in their Super Rugby clash in Pretoria on Saturday.

"Brumbies sides like to play phase-play in the vacuum, a retention kind of game and they do it well, so we have really taken notice of that," Ludeke said.

"They are playing fantastically at the moment and they are definitely a threat.

"They have made a huge improvement on their previous performances.

"When we prepared for them we saw that they were capable of scoring some great tries and can put you under pressure."

A victory will hold the Bulls in good stead ahead of their tour of Australasia in a fortnight's time.

A loss for the visitors, meanwhile, could further expose the warped conference system as the Brumbies should in reality be in sixth position on the overall log.

The Canberra-based team, on 24 points, are third overall, by virtue of leading their conference, while the Bulls, on 29 points, are in fourth place.

The Brumbies, however, should not be discounted as they have won four of their seven matches this season.

White, the former Springbok coach, has done wonders with a youthful side who could prove to be a stumbling block for the Pretoria giants.

The Bulls are fresh off a strong showing in their 32-18 victory over the Lions last week, recording their fifth win from seven matches.

Ludeke nonetheless felt his troops were far from the complete package and were looking for improvements on Saturday.

"We want to improve every week and we are definitely not satisfied with where we are as a team," he said.

"There are many areas that we want to improve in."

Bulls skipper Pierre Spies said it was crucial for his side to take the spoils this weekend before they embarked on their tour of Australasia.

"It is very important to get that momentum before going on tour," Spies said.

"We have the bye next week, so we have time to regroup.

"It is another vital game and we would like to end this phase on a high."