The All Blacks have reinforced their touring squad with the addition of prop Ofa Tu'ungafasi and lock Jamie Hannah after Ethan de Groot and Josh Lord were ruled out of Tuesday's match against the Emirates Lions following head injuries sustained in Saturday's opening Test.

De Groot and Lord both departed Ellis Park in the 37th minute after a head clash whilst competing at a Springbok ruck. George Bower and Simon Parker replaced the pair and held firm against the Springbok pack through the remainder of the 33-16 victory. Head coach Dave Rennie confirmed after the match that neither player would be available for the midweek fixture and cast doubt over their participation in the second Test.

"It was a head clash which is problematic and long-term," Rennie said. "Obviously neither of those guys can play on Tuesday. Probably can't play on Saturday; it depends on the protocols and what happened on the sideline."

The injuries compound a difficult tour for New Zealand, who have already sent four players home and are monitoring loose forward Anton Segner after he was withdrawn from the bench before kick-off with acute inflammatory arthritis in his ankle. Richie Mo'unga, Bradley Slater and Noah Hotham have been added to the squad in recent days, and now Tu'ungafasi and Jamie Hannah arrive as further reinforcements.

Tu'ungafasi, 34, brings 68 Test caps to the group but has not featured under Rennie, having missed selection for the Nations Championship. Hannah, 23, made his Test debut off the bench against France in July and has since represented the All Blacks XV on two occasions.

The midweek fixture against the Lions at Ellis Park offers Rennie a chance to rotate his squad ahead of the second Test, but the growing injury list narrows his options. De Groot had entered Saturday's match carrying illness from Friday's captain's run, and the head clash has now removed two forwards from contention at a time when depth is already stretched. How quickly the pair progress through return-to-play protocols will determine whether New Zealand can field their preferred pack for the remainder of the series.