New Zealand have called up wing Hosea Gear and fly-half Stephen Donald as replacements for Mils Muliaina and Colin Slade.
Full-back Muliaina and number 10 Slade are out of the rest of the World Cup after suffering injuries during the 33-10 quarter-final win over Argentina.
Muliaina was forced off at half-time with a fractured shoulder on the occasion of his 100th cap.
Slade suffered a partial tear in his left adductor groin muscle.
It is a similar injury to the one that forced star fly-half Dan Carter out of the tournament.
Slade stepped into the side after Carter's departure, but he in turn was forced off after half an hour against the Pumas, which brought third-choice Aaron Cruden into the fray.
Cruden is now set to start Sunday's semi-final against Australia, with Donald - who last played for the All Blacks as a replacement against Scotland in 2010 - likely to be on the bench.
Donald, 27, joined Bath after becoming frustrated by his lack of opportunities and missing out on the original World Cup squad.
"We've lost the first two blokes chosen and that's a setback, that's the reality of it," said head coach Graham Henry.
"We have a group of players who have been on standby. We didn't announce that group and we won't announce that.
"We've got less players here than overseas. Have we got the depth? We'll find out next week."
Despite the loss of his first two fly-halves, Henry was pleased on Sunday with the performance of 22-year-old Cruden, who has not played at Test level since last year and last took the field in the New Zealand domestic season, which ended more than a month ago.
"I think he did very well for a young guy who hasn't played a lot of Test match football," the coach added.
"He's got a lot of talent and he really enjoyed the experience. If you'd asked him a week or so ago whether he would be playing in a quarter-final of the Rugby World Cup he probably would have laughed at you."
Gear, 27, was a surprise omission from the original World Cup squad.
"Hosea was very close to getting in the squad initially...very very close, it was very tight," Henry added.
New Zealand switched centre Sonny Bill Williams to the wing against Argentina after injuries ruled out Israel Dagg, Richard Kahui and Zac Guildford.
The injury to 31-year-old Muliaina, who is moving to Japan after the World Cup, brings his All Black career to an end, having become the second player - after captain Richie McCaw - to win 100 caps for New Zealand.
"From today onwards, I will be a former All Black," Muliaina said on Monday, with tears in his eyes.
"It only sunk in that it was over about five minutes ago. I really wanted to have a finish in a couple of weeks' time but it is not to be. This is rugby. Last night I was on top of the world but it is like a roller coaster.
"Bitter disappointment... but I am particularly proud to be an All Black. I have enjoyed my time and met some amazing people."
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