Leinster have confirmed that Isa Nacewa and Jamison Gibson-Park have been denied entry to South Africa due to visa issues.
The squad arrived at the airport this morning but regulations brought in last January require New Zealanders to have obtained a visa to enter the country.
Leinster said in a statement this afternoon: "Leinster Rugby can confirm that both Jamison Gibson-Park and Isa Nacewa have not been granted a visa at this point in time and will as a result return to Dublin at the earliest opportunity.
"Nick McCarthy has been called up to the touring squad as a result and will arrive tomorrow.
"Leinster Rugby will be making no further comment on this matter."
The province take on the Southern Kings on Saturday afternoon in Port Elizabeth with a clash with the Toyota Cheetahs in Bloemfontein to follow on Friday week.