They are members of an 11-strong New Zealand development team that is being sent to Europe to gain experience in track and field racing at international level.
O'Shea (22), an accountancy student at the University of Otago, will compete in the 200m, 400m and his specialist 400m hurdles. Green (17) will contest the 800m, 1500m and 3000m.
O'Shea will compete at six meetings and Greene at four.
The first meeting for both athletes will be at Grenoble on June 22. O'Shea's last meeting will be at Heusden-Zolder, Germany, on July 16, and Greene's at Glasgow on July 17.
O'Shea's main goal in Europe is to crack the 50 second barrier for the 400m hurdles.
"I know from my 100m time of 10.47sec that it is well within my grasp," he said. "It's been a frustrating few years trying to achieve that goal."
The qualifying standard for the London Olympics is 49.40sec or a B-standard of 49.50sec.
The New Zealand record of 49.90sec was set by Nick O'Brien in 2003.
O'Shea was out of action for most of last season with an injury that affected his left hanstring, lest posterior cruciate ligament (PCL) and groin.
Greene was second at the world schools cross-country championships in Slovakia last year but knows she will meet stiffer competition this time.
She is targeting personal-best times to qualify for next year's world junior track and field championships at Barcelona.
