"Tui Kamikamica is currently in hospital following a medical episode on Monday morning," the club said on Monday afternoon.
"He has undergone treatment for a suspected stroke and is recovering in hospital.
"Tui is receiving the best possible care and is being supported by hospital specialists, alongside the Club’s medical staff. The club asks that Tui’s privacy is respected at this time. Further updates will be provided when appropriate."
Kamikamica had played in all four games for the Melbourne Storm this year, recently starting on the bench and completing his 142nd appearance for the club in their loss to North Queensland at the weekend.
He had recently signed a one-year contract extension to stay in Melbourne despite having been linked to English Super League club St Helens during the off-season.