Rodriguez was a serving New York cop based at Ground Zero on 9/11.
He was also the NYPD official soloist and sang at the funerals of over 100 police and fire brigade members who perished in the terrorist attacks.
For his service, he was chosen by President Bush to sing to the American nation at Yankee Stadium following 9/11.
Trained by Placido Domingo, Rodriguez shared the stage with his teacher at the service.
The duo, accompanied by Roger Buchanan, will sing the duets Because We Believe, The Prayer and Time To Say Goodbye and will include operatic soprano, Kathi Craig, in the trio Nella Fantasia from the movie, The Mission.
Craig's songs include There's No One Like You, Climb Every Mountain, Let It Be Me, My Heart Will Go On from Titanic, Somewhere from West Side Story with Rodriguez, and the Mozart duet, Sull'aria, which featured in The Shawshank Redemption.
Kavanaugh's repertoire feature Rejoice, Think of Me from Phantom, The Lord's Prayer and Requiem For A Soldier with Vicki Lee.
Rodriguez will sing This Is The Moment from Jekyll And Hyde, You Raise Me Up, Danny Boy and My Way, made famous by Frank Sinatra.
The Art Gallery, which seats 100 people, has been a favourite venue for the family because of its acoustics and provides an intimate setting for the concert.
The concert, 4.30pm, Sunday, August 2, at Te Manawa Art Gallery, also includes tea and coffee for guests on arrival.
Tickets $25 are available from Te Manawa reception.