Parry said: "I'm pleased to have been able to bring Luke in on loan. With Shaleum Logan suspended for two games we needed cover at right-back and Luke will provide that. He is a talented young defender who has a bright future ahead of him.
"I'd like to thank Leicester manager Nigel Pearson for allowing Luke to join us for a month."
O'Neill will be available for Tranmere's home games against Leyton Orient on Saturday.