From World Cup people's hero to scrapping for an All Blacks starting role - it's been a tumultuous 12 months for halfback Piri Weepu.

A wistful Weepu was reminded on Tuesday of his starring role when the All Blacks beat a gritty Argentina in the World Cup quarter-final last October.

His six penalty goals proved the difference in a dogfight which had the All Blacks leading by just two points with half an hour remaining, before pulling away late to win 33-10.

Social media burst into life after that game, labelling Weepu the saviour for a World Cup-hungry public still coming to grips with five-eighth Daniel Carter's tournament-ending injury.

Weepu's stocks have slumped somewhat as the Pumas lie in wait again in Saturday's Rugby Championship Test at Wellington.

The 28-year-old is firmly seen as the backup to dynamic No.9 Aaron Smith, who has started all five Tests this year.

Weepu has come off the bench in all of them to mirror a stuttering Super Rugby campaign at the Blues in which his game time was limited while he underwent a high-profile battle with conditioning.

He admitted it was hard to assess whether his form was getting back near the giddy heights of last year's World Cup knockout phase.

"I haven't had a lot of rugby to say whether I have or not," he said.

"I guess once I get a better understanding of how my game fitness is going, I'll probably have a reasonable understanding from there."

Of Weepu's 61 Tests, 39 have been off the reserve bench.

He seems set to extend his record as the most prolific All Black substitute in Test history.

If he makes bench appearance No.40, he will be outright second on the all-time list, moving ahead of Ireland's Ronan O'Gara and sitting only behind South African "super sub" prop Ollie Le Roux, who started 43 of his 54 Tests off the reserve bench.