South Africa's Cape Town Opera has turned down an appeal from Nobel Peace Prize winner Archbishop Desmond Tutu to call off a tour of Israel.
He said it would be as inappropriate as it had been for international firms to visit South Africa during apartheid.
But Cape Town Opera's managing director said the company was reluctant to take the political stand of shunning cultural ties with Israel.
An Israel government spokesman told the BBC such boycotts did not aid peace.
The opera's production of Porgy and Bess will be performed in Tel Aviv next month.
In his letter the archbishop, who retired from public life earlier this month, said it would be wrong for the Cape Town singers to perform "in a society founded on discriminatory laws and racial exclusivity".
He said the tour should be postponed "until both Israeli and Palestinian opera lovers of the region have equal opportunity and unfettered access to attend performances".
"Only the thickest-skinned South Africans would be comfortable performing before an audience that excluded residents living, for example, in an occupied West Bank village 30 minutes from Tel Aviv.
"To perform Porgy and Bess, with its universal message of non-discrimination, in the present state of Israel, is unconscionable."
Israeli government spokesman Andy David said boycotts were not the way forward and cultural tours were the best way to bring peace in the violent region.
"Cultural relations sending messages of peace and co-operation - that's the only way to promote peace," he told the BBC's Focus on Africa programme.
Mr David also dismissed any comparison between apartheid South Africa and Israel.
"There are no discriminatory laws in Israel, there are no racial issues in Israel - we have Arabs in the government."
The spokesman added that he felt that the archbishop's comments were "one-sided" and were a cause for concern.
"I think that people from the opera who never visited Israel are listening to vicious propaganda against my country."
'Food for thought'
Cape Town Opera's managing director said he believed in the "transformative power of the arts".
"I am proud that our artists, when travelling abroad, act as ambassadors and exemplars of the free society that has been achieved in democratic South Africa," Michael Williams said in a statement.
He said the company was "reluctant to adopt the essentially political position of disengagement from cultural ties with Israel or with Palestine".
Mr Williams said was aware of the possibility of being seen as partisan, so has ongoing negotiations to perform within the Arab world.
"In particular, Cape Town Opera welcomes the opportunity to perform within Palestine as well," he said.
The production of the Gershwin opera has "much which should provide food for thought for audiences in Israel", he added.