The Canterbury Crusaders say they are treating Friday's clash against the table-topping Waikato Chiefs as a "semi-final", as they look to secure a berth in the Super 15 play-offs.

Going into the penultimate week of the round-robin series, the Crusaders are among eight teams battling for the remaining three places in the top six.

Only the Chiefs, Northern Bulls and ACT Brumbies are assured of qualifying while the Crusaders, Queensland Reds and Central Cheetahs are best placed to grab the remaining places.

The NSW Waratahs, Auckland Blues, Coastal Sharks, Western Stormers and Wellington Hurricanes are mathematical possibilities but are reliant on other results.

The Crusaders, currently in fifth place, need to beat the Chiefs, then defeat the Hurricanes in the final round next week to secure fourth place and a crucial home play-off.

Both the Crusaders and Chiefs welcome back several All Blacks who were rested last week after the Test series against France -- with Kieran Read, Wyatt Crockett, Owen Franks and Luke Romano starting for the Crusaders and the Chiefs regaining Sam Cane.

"All you can do is to make sure the intensity is right and you give your all," Crusaders' captain Read said.

"Our mental shift is that this is a semi-final and a game that has to be won."

The clash also serves as a de facto All Blacks trial in key areas.

The Crusaders' Matt Todd lines up against incumbent Test openside flanker Cane, discarded World Cup scrum-half Andy Ellis faces emerging international Tawera Kerr-Barlow while Dan Carter clashes with his heir apparent playmaker Aaron Cruden.

The Cheetahs, who have a guaranteed four points from a bye next week, need to make amends for last week's setback at the hands of the Stormers when they play a weakened Blues side who are without injured halves Piri Weepu and Chris Noakes.

The Cheetahs lie sixth, five points adrift of the Crusaders, two clear of the Blues and Waratahs and four ahead of the strongly finishing Stormers and Sharks.

The Waratahs, like the rest of the Australian sides, have a bye this week as Australia play the British and Irish Lions in the third and series-deciding final Test Saturday.

The Stormers head to Port Elizabeth on Saturday needing to beat the Southern Kings before their final hurdle next week against the Bulls who have already won the South Africa Conference.

Stormers coach Allister Coetzee said his side must not be complacent after their impressive 28-3 win against Cheetahs a week ago.

"I was obviously very pleased with the Cheetahs game, and it gives one confidence, but our plan has always been to win these last three games; that's where the focus is."

The Sharks, needing to win their last two starting with the Bulls in Pretoria on Saturday to have a chance of qualifying, are no strangers to relying on a late surge to get them through.

Co-coach Grant Bashford is eyeing maximum points against the Bulls and then the Kings next week.

"Anything less than that won't be good enough. We thought we were out of it, but thanks to the results of last week, we feel we have a realistic chance."

The Sharks beat the Blues last week. If they defeat the Bulls and the Blues beat the Cheetahs, it would intensify the competition for sixth place going into the final round.

The Hurricanes, with an outside chance of qualifying, need maximum points against bottom of the table Otago Highlanders to keep their remote mathematical chance alive and would have to repeat the performance next week against the Crusaders.