Cape Town - Springbok assistant coach Matt Proudfoot says the All Blacks lock duo of Brodie Retallick and Sam Whitelock spell danger ahead of Saturday's Rugby Championship encounter in Wellington.

The Bok forwards guru addressed reporters in the New Zealand capital when he said the All Blacks duo have revolutionised lock play in recent years.

He pointed to Retallick's intercept try in the 20-16 win over Argentina in Buenos Aires last weekend.

"Watching Brodie again on the weekend taking an intercept, second rowers doing that type of work, I suppose they have shifted the bar as every generation does," Proudfoot said, as quoted by the Stuff.co.nz website.

"I don't know how many Tests it is, 50-60 Tests they've been together as a unit, but that experience really bodes well for them. Our guys are relishing that challenge, just to see how their game has expanded," Proudfoot said.

The Springboks currently have four locks in their squad, namely Eben Etzebeth, Lood de Jager, Franco Mostert and Mavin Orie, while the likes of Pieter-Steph du Toit and Rynhardt Elstadt can also be utilised in the second row.

"We challenge our players on a weekly basis to improve and to get better and I'm really happy with the four we've got, I think they've had great seasons and I think it's a part of the game that's going to be fascinating; the lineout, what the four second rowers get up to defensively, carrying the ball up, contesting ball in the air."

Saturday’s Test us scheduled for 09:35 (SA time).