All Blacks coach Steve Hansen wary of growing threat to rugby's international crown from the North

All Blacks coach Steve Hansen is wary of Northern hemisphere rugby which he says is "humming along nicely"

His comments come at the first of four so-called "Foundation Days".  

The Christchurch session involves around a dozen South Island All Blacks, and its timing is curious with the likes of Highlanders stars Aaron and Ben Smith mixing it with a whole host of Crusaders just days before the two sides clash in Dunedin this Saturday.   

The 'camps' have been criticised by some as being disruptive, but New Zealand rugby says they are a necessary evil ahead of another busy international season. 

Speaking of which, Hansen has been a keen observer of the Six Nations, as the All Blacks eye up tests against France, England and Ireland later in the year.

France's 22-16 win over England was Eddie Jones' team's second loss in a row, and with Ireland beating Scotland they now have wrapped up the Six Nations, and have only to beat England at Twickenham this weekend to secure the Grand Slam.

The All Blacks play France in three tests here in June.

"Northern hemisphere rugby is humming along nicely," said Hansen today, "It's going to be a good challenge".

"France is a side as we know turn up or turn off, when they turn up they are extremely hard to play".

The much anticipated test against England is set down for November 10, with Ireland in Dublin a week later.

As well as the four foundation days - in Christchurch, Wellington and Auckland - there will also be two extended camps in May to get the side ready.

The Auckland camp is May 20-21  and that means  the Chiefs' All Blacks won't be available for their match against the Sharks in Durban on May 19.

"Whilst everyone's happy not about it, " Hansen said , "I'm not either, but it is what it is".