Delays in diagnosis and treatment of the most common cancer in Australia will have lasting consequences beyond the coronavirus pandemic, the National Breast Cancer Foundation warns.

The foundation has marked the start of Breast Cancer Awareness Month by forewarning an expected rise in later-stage breast cancer diagnoses in years to come, noting surgical delays of 12 weeks can result in 500 more breast cancer deaths a year.

It estimates there could be between 1,300 and 2,600 missed or undiagnosed breast cancer cases based on Cancer Australia data released this week.