Also invited to join the squad are Scotland lock Ali Kellock (Glasgow), and the South African trio of centre Juan de Jongh (Stormers), scrum half Sarel Pretorius (Cheetahs) and fly half Marnitz Boschoff (Lions).
Three Argentina internationals are on duty against Australia before joining the Pumas' European tour. Full back Joaquin Tuculet, scrum half Tomas Cubelli and lock Matias Alemanno all featured in the 21-17 win over Australia in Mendoza earlier this month.
That gives Kirwan 27 players to work with when the squad assembles in London next week, including former England prop Matt Stevens and Australia wing Nick Cummins. CJ Van der Linde, though, has withdrawn following injury.
Barbarians squad
Backs (12)
Tim Nanai Williams (Chiefs)
Joaquin Tuculet (Grenoble & Argentina)
Patrick Osborne (Highlanders)
Frank Halai (Blues & New Zealand)
Juan de Jongh (Stormers & South Africa)
Nick Cummins (Coca Cola West Red Sparks & Australia)
Francis Saili (Blues & New Zealand)
Colin Slade (Crusaders & New Zealand)
Marnitz Boshoff (Golden Lions & South Africa)
Tomas Cubelli (Belgrano Ath & Argentina)
Sarel Pretorius (Cheetahs)
Fumiaki Tanaka (Highlanders & Japan)
Forwards (15)
Coenie Oosthuizen (Cheetahs & South Africa)
Matt Stevens (Sharks & England)
Thomas Du Toit (Sharks)
Angus Ta'avao (Blues)
James Parsons (Blues)
Mahonri Schwalger (Chiefs & Samoa)
Michael Rhodes (Stormers)
Matias Alemanno (La Tablada & Argentina)
Dominic Bird (Canterbury & New Zealand)
Al Kellock (Glasgow & Scotland)
Adam Thomson (Canon Eagles & New Zealand)
Matt Todd (Crusaders & New Zealand)
Steven Luatua (Blues & New Zealand)
Heinrich Brussow (Cheetahs & South Africa)
Jacques Botes (Sharks)