New Zealand opera singer Dame Heather Begg has died in Sydney, less than a month after adding the title Dame to her name.

Dame Heather, 76, died on Tuesday after a long illness, her death notice said.

Governor-General Sir Anand Satyanand announced on April 17 that her title had been redesignated from Distinguished Companion of the New Zealand Order Of Merit (DCNZM) to Dame Companion of the New Zealand Order of Merit (DNZM).

Government House had announced her redesignation early because of her ill-health.

Dame Heather was appointed a DCNZM in the Queen's Birthday Honours in 2000 for her services to opera.

She also had an OBE.

The Government decided in March to restore the titles of knights and dames to the honours system.

The mezzo soprano had a distinguished career in New Zealand, Australia and Britain, having performed with opera companies including the Royal Opera, Sadlers Wells and the New Zealand Opera Company.