"I am just so happy at this result, so happy to have the qualification and know that I can concentrate now on preparing for London," he said. "You can't exactly say I have had good luck when it comes to the Olympic Games over the years."
Gemmell was controversially left out of the 2004 Athens Olympics team, before being selected for Beijing four years later only to sustain an injury in the lead-up to the event which forced him to withdraw.
Bevan Docherty did his chances no harm, finishing in 12th place with another consistent performance. The two-time Olympic medallist has made it clear he is aiming to peak in London, so no doubt has plenty of improvement in him over the months ahead.
Ryan Sissons could not impress the selectors due to a crash on the bike, with early reports suggesting the 23-year-old suffered a broken nose and facial cuts, while Elvery paid the price for a brave bid on the bike as he faded badly on the run.
Earlier, Hewitt raced superbly for third behind Australia's Erin Densham and Helen Jenkins from Great Britain but, having already booked her place in London, the pressure was on the other Kiwis to make the top eight and join her on the Olympic team.
Nicky Samuels came closest to the top eight, running a very good second half of the 10km run to come home 12th, one minute 22 seconds behind race winner Densham and just 14 seconds outside eighth.
Debbie Tanner faded slightly on the second half of the run, coming home in 20th and Kate McIlroy simply couldn't get things going on the run, finishing a disappointing 27th.
McIlroy has been in good form so far this season and is expected to get the nod, meaning the final spot could come down to a straight choice between Samuels and Tanner.
"I wanted top eight but, first Kiwi that hasn't qualified, that should help," Samuels said. "I was really close to the top eight but not quite there but I am confident I can come out and do it again.
Tanner has her fingers crossed for a return to the Olympic Games after finishing 10th in Beijing in 2008.
"I was second Kiwi home in London after being ill and today I am third Kiwi home, so hopefully that shows the selectors that I can be consistent and get up there and be amongst it. I am only moving forward so hopefully I can get on the team and represent New Zealand at the Games."