Gill hurled the shot 19.93m with his second throw, which saw him clear the qualifying mark of 19.75m and he will join Canterbury's Tom Walsh in Scotland providing his nomination to the New Zealand Olympic Committee is approved.
Walsh, who recently won a bronze medal at the World Indoor Championships in Poland, took the New Zealand title from Gill with a 20.79m effort in his final round, which was the best throw on Kiwi soil.
Their duel was the highlight of the second day of the national championships at Newtown Park, which also featured a tightly-contested women's 800m race, which Angie Smit won in 2:01.53, ahead of rival Nikki Hamblin (2:03.23).
"I came here to compete and my coach [Steve Willis] said to me 'put pressure on Angie for as long as you can and just hang on, hang on' and I definitely hung a lot closer to her than I did four weeks go so we are heading in the right direction," Hamblin said.
Brad Mathas won the men's 800m final in 1:53.71, with Benjamin Anderson second in 1:54.43.
As expected, Valerie Adams breezed to her 13th national shot put title with a world-leading mark for the year of 20.46m.
Adams was a big-name attraction at a windswept Newtown Park and was busy signing autographs and posing for photos after her event.
In the women's discus, Siositina Hakeai achieved the B qualifying standard for Glasgow of 58.50m for the second time with a winning throw of 58.77m as she comfortably claimed the national crown ahead of Te Rina Keenan (52.49m).
Auckland's Sarah Cowley won the women's high jump as she cleared 1.84m but was unable to make the B standard for Glasgow of 1.88m.
- Daniel Richardson of APNZ
