Fly-half Cruden, drafted into the All Blacks' World Cup squad less than a fortnight ago as replacement for an injured Dan Carter, will wear the number 10 shirt in Sunday's semi-final at Eden Park.
With Carter's understudy Colin Slade also out of the competition through injury, Cruden has been handed the playmaker role opposite Wallabies fly-half star Quade Cooper.
"It's definitely the biggest game of my life and a huge challenge that I'm really looking forward to," Cruden said.
"Against Australia, it's always an epic battle. Throw a semi-final into the mix and it's huge.
"The more you are involved in the game the more you're able to grow in confidence.
"I suppose if they are going to target me then it will give me more of a chance to be involved in the game and grow my confidence and become more comfortable out there."
All Blacks coach Graham Henry, meanwhile, has no doubt that Cruden is up to the task following his appearance as a substitute against quarter-final opponents Argentina six days ago.
"He is the man this week," Henry said.
"Last week he was a sub, so it is a big change for him, but he's a bright rugby player, he knows the game well. He has captained a lot of teams he's been in, so he directs the traffic well.
"It's the biggest game he's played in, it's the biggest game a lot of them have played in, quite frankly, so I am sure it's challenging. But he seems to be handling it well."
New Zealand lost to Australia the last time the countries met in the final game of this year's Tri-Nations tournament, but Henry added: "This is a totally different focus.
"It is a World Cup semi-final, and if they are not focused now they will never be focused, simple as that. There are no excuses for us.
"I think there's a quiet focus there, a quiet determination.
"The guys have been a bit quieter than normal, probably because it's such a huge game. It's probably the biggest game these guys have played in 10 years.
"It happens to be Australia. They are like big brother to us, I guess, in many ways. A country of 20 million competing with four-and-a-half million, and that is a positive relationship I think. It brings the best out of New Zealanders.
"But as far as this rugby tournament is concerned it's a semi-final we need to win to win a cup, and it so happens that it's against Australia.
"We know them, they know us well, there's a lot of rivalry, but I don't think it's any different to playing anyone else in the semi-final of a Rugby World Cup. You have just got to do the business."
Gilbert has released a new line of rugby cleats. The Gilbert Virtuo 8S is part of the exciting new product. Check it out.
The entire All Blacks apparel line has been updated for 2013/14. Check out the New Zealand All Blacks polo.
The Nike Tiempo is a solid rugby cleat and one of few styles still made from full-grain natural leather.
The Gilbert Blitz 8S rugby cleat is a great cleat at a great price of $69.99. Get a new pair of cleats today.
A cool looking all black rugby cleat with the high performance adidas is known for. Get in the Gear!
Wear the crest of the British and Irish Lions on your t-shirt. A great look for the summer.
The All Blacks Performance t-shirt is black with hints of blue from the training jersey. Very Cool.
The New Zealand All Blacks training jersey for 2013/14. Get in the Gear!
The USA Rugby Pro Alternate rugby jersey is perfect for any fan of the Eagles. Get yours to wear during the summer Test matches.
The NEW All Blacks 2013/14 jersey has arrived at World Rugby Shop. Dare to wear the colors of the All Blacks.