Forbes picked up a foot injury at last month's Tokyo tournament and was forced to withdraw. Toby Arnold, Sam Dickson, Mark Jackman and David Raikuna were also not considered because of injury.
Coach Gordon Tietjens said the injuries had made selection particularly challenging but he was happy with the mix of young and experienced players in the team.
Returning from injury are IRB Sevens Player of the Year Tomasi Cama, who missed Hong Kong and Tokyo, Kurt Baker, who has not played since Wellington, and Scott Curry, who makes his first squad of the season.
Back Pita Ahki is the only new cap. The 20-year-old is a member of the Blues wider training group and played for New Zealand under-20s at last year's junior world championship in South Africa.
"We have played consistently well all season despite a number of injury setbacks so it shows the depth we now have in the wider squad," Tietjens said.
"We are determined to end the season on a high note so we are looking for top performances in Glasgow and London which will hopefully seal the series for us.
"While it's disappointing not to have DJ on the team, we're hoping this gives him plenty of time to come right for Moscow for the Rugby World Cup in late June. That's a key event for us in terms of our build-up for Rio in 2016.
"Tim did a great job stepping up to the captain's role in Tokyo and certainly deserves the honour of leading the team again."
New Zealand hold a commanding 32-point lead over South Africa after seven of the nine legs of the series. The Glasgow tournament starts on May 4.
New Zealand sevens squad for next month's Glasgow and London legs of the Sevens World Series: Pita Ahki, Kurt Baker, Tomasi Cama, Scott Curry, Gillies Kaka, Rocky Khan, Ben Lam, Tim Mikkelson (c), Lote Raikabula, Sherwin Stowers, Trinity Spooner-Neera, Belgium Tuatagaloa.
