Southee, Guptill not safe after lean series

Departing captain Brendon McCullum suggests Tim Southee's international place is no longer assured following a disappointing summer against Australia.

A world class operator in recent seasons sharing the new ball with Trent Boult, Southee was well below his best in the five trans-Tasman Tests.

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His nine wickets came at a cost of 565 runs with an average of 62.8 which was only superseded by struggling offspinner Mark Craig's 66.7 runs per wicket among the specialist bowlers.

Left-armer Boult (18 wickets at 42.1) was better but also failed to meet lofty standards as he battled to extract his trademark swing.

"Trent and Tim in particular will be disappointed with their series but that's the way it goes sometimes and I'd expect them to bounce back," McCullum said. 

However, a long queue of Test seam candidates including Neil Wagner, Matt Henry, Doug Bracewell and uncapped express paceman Adam Milne means the likes of Southee can take nothing for granted.

The right-armer hasn't been helped by a string of recent injuries either, McCullum said.

"He is a strong leader in the group but Tim's got some challenges in the next little while.

"There's other guys coming through who are performing very well, Matt Henry in particular, and it's going to push Tim to make sure he's operating at his best which we saw for a good 12-18 months."

Southee is not the only concern for the Black Caps.

Opening batsman Martin Guptill struggled against Australia this summer, averaging just 16.3 across the five Tests on either side of the Tasman.

New Zealand coach Mike Hesson identified Australia's prolific top five batsmen as the biggest difference between the teams.

David Warner, Joe Burns, Usman Khawaja, Steve Smith and Adam Voges averaged more than 75 runs each per innings against the Black Caps attack. 

Only Ross Taylor (81.0) and Kane Williamson (63.3) produced an average greater than 36 among New Zealand's specialist batsmen.

Just once in 10 innings did their team pass 375, when Taylor unfurled his 290 in the drawn Test at Perth.

An injured Taylor missed the two Tests in New Zealand but Hesson wouldn't blame all his team's struggles on that.

"The top five of Australia outplayed us," Hesson said.

"Ross is an experienced player and no doubt would have made a contribution in these two Tests. But it would be glossing over a few things if we felt one player would make a difference."

New Zealand's problems started at the top, where Guptill scored 163 runs in 10 innings while Tom Latham, who averaged 29.9, was often guilty of getting established but failing to push on for a big score.

Guptill is one of the world's premier limited overs batsmen but his technique against the new ball was ruthlessly exposed by Australia. 

His career Test average has sunk below 30 but Hesson says the 29-year-old still has the ability to thrive in the longer form, pointing to his 156 against Sri Lanka in Dunedin in December.

That was Guptill's only score above 50 in his last 14 Test innings.

"Martin still hasn't quite nailed it at Test level but again we think he has some good qualities," Hesson said.

"No doubt we need to tweak a few things but we still have a lot of confidence in Martin."

Hesson won't consider shifting Guptill to the middle order to replace the retired McCullum.

He says Henry Nicholls showed enough in his first two Tests to be given further opportunity.