Blues coach Sir John Kirwan knows a thing or two about rugby wings and has given the late-blossoming Frank Halai a huge vote of confidence.

Halai has been a star of the opening two rounds of Super Rugby, scoring four tries as the Blues demolished the Hurricanes and Crusaders.

With All Blacks right wing Cory Jane out for the season with knee problems, there's a gap at the highest level. New Zealand coach Steve Hansen has admitted he is impressed by the early work from Halai and his Blues wing partner, George Moala.

At 1.95m and 105kg, Halai is an imposing figure, much like Wellington's Julian Savea, who burst on to the test scene in extraordinary fashion last year.

No one is getting too carried away at the Blues - Kirwan's trying to keep a lid on emotions after their stunning start.

But he was prepared to discuss Halai when asked why the 25-year-old had gone under the radar until now.

Halai dedicated his early career to sevens and debuted in the NPC for Counties Manukau only last year.

But he did enough to gain the attention of Kirwan, the legendary All Blacks wing who scored 35 tries in 63 tests and changed the dimensions of the position with his size, pace and power.

"This is a really interesting sport. Sometimes things pass you by . . . you miss a moment because you go with the sevens, then you come back [with] a bit more self-confidence, a little bit more maturity," Kirwan said of Halai.

"I really believe in him. I think he's going to be outstanding. He's a really intelligent rugby player. He knows what he needs to do and he's a very quick learner.

"So it's about opportunities sometimes and he's probably had a couple and is disappointed that he's let those little opportunities go by. So we've said, ‘your turn, away you go' and he's been outstanding."

Halai has been virtually unstoppable close to the try line. His long-range game will face more examination, as will his defence.

Some of that is sure to happen on Sunday at Eden Park when the Blues host the Bulls, who have the pin-point kicking game of Morne Steyn coming from first-five.

It will be a good challenge for Halai.

"Our back three are going to have to be really alert," Kirwan said.

"The Bulls are going to throw really different stuff at us. I think this is the most difficult game from a philosophy point of view."

- © Fairfax NZ News