Former All Blacks scrum-half Justin Marshall has claimed the Springboks are "undercooked" heading into Saturday's opening Test of the Rugby's Greatest Rivalry Series at Ellis Park.

Speaking on The Good, The Bad & Rugby Australia & New Zealand podcast, Marshall argued that New Zealand hold a preparation advantage despite both sides managing injury concerns. Whilst the All Blacks have utilised most of their touring squad in matches against South African URC franchises, the Springboks have seen key players only recently return to action.

Eben Etzebeth, Sacha Feinberg-Mngomezulu, Lood de Jager, Canan Moodie and Ethan Hooker all featured in South Africa's final match against Argentina, with Ox Nche and Franco Mostert potentially available for the New Zealand fixtures having last played in July.

Marshall suggested the Springboks deliberately employed a limited gameplan against Los Pumas to avoid revealing their hand. "They had that Argentinian game where they 100% went out there with a game plan to show absolutely nothing to the All Blacks," Marshall said. "If they play like that against us, we'd smash them by 30 points, given the fact that they kicked so much ball away and a lot of it reasonably aimlessly."

The former scrum-half acknowledged the conservative approach served a purpose, allowing Feinberg-Mngomezulu and others to accumulate minutes after injury layoffs. However, he maintained that New Zealand's greater recent match exposure leaves them sharper for Saturday's encounter in Johannesburg.