Opera Australia is facing pressure to sack a Georgian opera singer due to perform with the company next month over comments in which she compared gay and lesbian people to faecal matter.

The soprano, Tamar Iveri, has been rehearsing with Opera Australia in Sydney for several weeks ahead of a performance in Opera Australia’s Otello in Sydney in July and August.

Tamar Iveri (left) in A Masked Ball. The La Fura del Baus production opened Opera Australia's 2013 Melbourne season. Credit:Prudence Upton

Iveri is also scheduled to sing in Tosca in Melbourne in November and December.

Asked whether Iveri would still perform in both productions, an Opera Australia spokeswoman said the company had no comment.