Southby was named yesterday by Netball New Zealand as one of four coaches to join the Silver Ferns in international competitions this year.
Noeline Taurua will help in the Constellation Cup in September - a series between Australia and New Zealand - while the following month Southby will help coach the national side in the quadrangular tournament in Australia.
New Zealand, Australia, South Africa and England will be the nations in the tournament.
Gail Parata will help the national team when the tournament moves to New Zealand, while Deb Fuller will assist in the FastNet series in November in Auckland.
Southby co-coached a FastNet New Zealand side in Liverpool two years ago and she said it was a great opportunity to be involved again with the national side.
"Obviously, it is always good to coach at this level and have the chance to work with the best players . And you get the chance to work in with Wai [Silver Ferns coach Waimarama Taumaunu ] and the team," she said.
Southby will continue to coach the New Zealand under-21 squad, which plays in a tournament in Melbourne in August.
The side will take on other age-group sides from Australia, England, South Africa and Samoa in a warm-up for the Junior World Championships in Glasgow next year.
But the future was far from Southby's mind yesterday as she was digesting the last-minute loss of her Steel side to the Tactix in Invercargill on Monday night.
The Steel led for all of the game until the final 10 seconds when the Tactix went ahead to bag the victory 62-61. It was the Steel's eighth loss in a row.
Southby said the team was devastated after the game to lose and it was hard to take.
"But we just slipped off that defensive pressure and letting it go in attack and having confidence in our attack.
"When we did do that for periods we went ahead."
She said the side was not ruthless enough, and part of that came down to experience.
The side was learning all the time but it was a long process and would not happen overnight.
Former Silver Ferns captain Adine Harper was brought on in the third quarter and Southby said it was done to create a spark in the side.
It worked for a while but the side could not quite finish off.
Southby questioned the aggressive approach of the Tactix, saying they had twice as many penalties as her side.
"That sort of stuff wears you down. Just the pushes in the back and on the shoulder. It all catches up with you."
No player has been ordered off the court this season for repeated infringements, and Southby said perhaps that could be done to clamp down on the rough play.
The Steel will travel to Sydney this weekend to take on the Swifts in their penultimate game of the season, on Sunday afternoon.
