The Melbourne Symphony Orchestra (MSO) has cancelled acclaimed pianist Jayson Gillham's upcoming recital after comments he made on Gaza.

The pianist premiered 'Witness', a piece dedicated to the Palestinian Press at a show with the MSO on Sunday.

The composer was scheduled to perform again on Thursday August 15 however the MSO has said it was reworking its programme after the comments.

Before debuting the piece, which was penned by Connor D'Netto, Gillham introduced 'Witness' by saying Israel had killed more than 100 Palestinian journalists in Gaza.

"Over the last 10 months, Israel has killed more than 100 Palestinian journalists."

"A number of these have been targeted assassinations of prominent journalists as they were travelling in marked press vehicles or wearing their press jackets" he said.

"The killing of journalists is a war crime in international law, and it is done in an effort to prevent the documentation and broadcasting of war crimes to the world," Gillham added.

"In addition to the role of journalists who bear witness, the word Witness in Arabic is Shaheed, which also means Martyr" concluded the pianist.

In an email to ticketholders of Sunday's pefromance, the MSO said they were blindsided by Mr Gillham's comments and he had put them in a "difficult situation".

"They were an intrusion of personal political views on what should have been a morning focused on a program of works for solo piano," the email said.

"The MSO does not condone the use of our stage as a platform for expressing personal views.

"The MSO understands that his remarks have caused offence and distress and offers a sincere apology."

The email described the D'Netto piece as "a late addition to the advertised program," accepted for performance at Mr Gillham's request.