Hesson has led the Volts to two titles in the last five seasons and has coached New Zealand A and development teams during the past four years.
The latest promotion is another vote of confidence in his ability and perhaps a sign from New Zealand Cricket he remains in the mix for future appointments.
Former Black Caps batsman Mark Greatbatch assumed the reins in February after Andy Moles stepped down in October following pressure from the team's senior players.
"I'm just one of the coaching staff and will help where I can," Hesson said when asked yesterday about his role with the New Zealand team.
"The Black Caps trainer, Bryan Stronach, is away getting married so that opened up an opportunity to bring in an extra coach.
"Hopefully, I can offer a few new ideas and bring some enthusiasm.
"It is also about learning to work as a group of coaches on the international scene and it is something that I'm certainly looking forward to."
Hesson will stay with the team for the remainder of the five-game one-day series against Australia and the first test in Wellington beginning on March 15.
"It is certainly a great series to be involved in and I'm obviously keen to learn as much as I can but also contribute where I can as well."
Hesson is employed by the Otago Cricket Association but is not on a fixed-term contract and told the Otago Daily Times in April he was nearing the end of his tenure with the province, saying he had "one or two more years".
When asked about rumours he was heading overseas at the end of the season, Hesson responded: "It is definitely just a rumour at this stage.
"In fact, it is the first time I've heard it."
Former Otago coach Vaughn Johnson will take over the Otago reins but Hesson said it was also an opportunity for the senior players to step up as well and "help wherever they can".
