Buenos Aires - Argentina coach Mario Ledesma offered hope on Sunday to teams who will challenge New Zealand in the 2019 Rugby World Cup, saying the world champions are not "untouchables".

The All Blacks are 11/10 favourites with some bookmakers to win the tournament a third consecutive time next year in Japan, the first Asian country to stage the rugby showpiece.

But former Pumas hooker Ledesma was not impressed with New Zealand, despite their 35-17 victory in Buenos Aires Saturday clinching a sixth Rugby Championship title.

The win over the Pumas came two weeks after the All Blacks were stunned 36-34 in Wellington by South Africa.

"I thought the All Blacks were not very clinical," said Ledesma.

"They dropped the ball a lot and lost a lot of lineouts. They are not untouchables.

"It was not the normal New Zealand team that we played against, but we failed to take advantage of the situation.

"My team made as many line breaks as the All Blacks only to waste scoring opportunities while they took full advantage of theirs."

Ledesma also slammed his team after suffering a third defeat in five matches since succeeding Daniel Hourcade as coach in the middle of the year.

"All I asked of my boys before the match was that they should be themselves, but I did not recognise some of them at times.

"Had we played better, especially during the first half, the All Blacks would have come under a lot more pressure.

"We struggled in the set pieces and it was embarrassing to watch New Zealand dominate us in the scrums.

"What really upset me was that we did not do the simple things, the basics, properly. You cannot fail to do that and hope to beat the All Blacks.

"Some of the scrums and lineouts offered attacking opportunities for us and we failed to take them," lamented the 45-year-old coach, who won 84 caps for the Pumas.

Argentina skipper and hooker Agustin Creevy backed Ledesma, saying: "We were not ourselves during the first half."

A Rieko Ioane brace helped New Zealand establish a 21-3 lead by the break, but the second half was more even with both teams scoring two converted tries.

New Zealand have 21 points, South Africa 14, Argentina eight and Australia five going into the final Rugby Championship fixtures this Saturday.

The Springboks confront the All Blacks in Pretoria and the Pumas tackle the Wallabies in Salta.