All Blacks legend Sir John Kirwan candidly declares he's under pressure as his Blues prepare to face defending Super Rugby champions NSW Waratahs on Saturday.

But the coach insists it doesn't worry him and he remains committed to building a successful new culture at the Auckland-based franchise - even if he's not around to enjoy it. In a frustrating start to their campaign, the Blues have suffered five narrow losses and the sorry run of outs has led to calls for Kirwan to be axed.

"Look, I'm under pressure," Kirwan said at Friday's captain's run at Allianz Stadium. "I'm under pressure because I care about the fans and care about the job I'm supposed to be doing - and that's winning. We get paid to win. But you can't worry about that and I'm not worried about it because all I can focus on is what I can control. So everyone was calling for my head a couple of weeks ago and I can understand that. It's part of the job."

The Blues were the dominant force when Super Rugby began, landing titles in the first two seasons in 1996 and 1997. But the Auckland-based side have only reached the finals twice since winning a third championship in 2003.

Kirwan said he'd been lured home in 2013 after coaching stints in Italy, Japan and Europe to "change a culture of a club".

Sir John Kirwan is fast running out of excuses as Blues coach © Getty Images

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"And we're doing that," he said. "There's going to be some pain and I might not survive to see the good days. But if you start worrying about that, you never get your job done. I'm really confident in the football team I have. I'm confident in the job we're doing and I'm really confident that the club's heading in the right direction.

"We've got a really good board, we've got a really good CEO, we're investing in the business, we're changing to a new facility and the team is in great shape. We just haven't won a football game. If you'd had a look at our games, we've got one (bonus) point out of (almost) every game, but we need to turn our season around."

Kirwan is predicting "fireworks" from "two physical sides going at each other" when his Blues clash with the Waratahs. And Waratahs coach Michael Cheika is predicting Kirwan is going nowhere regardless of the result, suggesting the Blues would be mad to let the rugby knight go.

"There is no chance John Kirwan will lose his job. That's not happening," Cheika said on Friday. "It doesn't happen in New Zealand. That's number one. They're very focused about the long-term over there with the way their provincial system works.

"Kirwan's done such a great job over his whole coaching career. The reality is if you look at their results they've only just missed out in nearly every game and three of those have been away, if I'm not wrong. He's got too much experience. Why would you (sack him)? I don't understand why people would think that."