Tania Kelly looked forward to Daffodil Day each year, then everything changed.

The 55-year-old was diagnosed with bowel cancer on the day of the national fundraiser in 2022, and went on to have surgery to remove a lesion before she experienced severe reactions to chemotherapy.

What was once a day to raise sorely needed money to fight against cancer, and bring some lightness to Melbourne's dreary winter CBD, turned nightmarish.

"I thought maybe it was just a polyp or something like that, but it's actually hearing the word 'cancer' ... it was pretty devastating," Ms Kelly told AAP.

"I thought, 'Of all days (to be diagnosed), this is my most favourite day of the year at Rialto'."

After a switch to oral chemotherapy, though, Ms Kelly received good news in March this year - she was in remission, with doctors to keep a close eye on her over the next five years.

Daffodil Day has since taken on a different meaning for the 55-year-old, who has enjoyed the day for its sense of connection since she began working at Rialto, a well-known Melbourne skyscraper, in 2017.

The building has held an annual Daffodil Day event for several years.

"I was always aware of the amazing work that the Cancer Council does, but (the day has) taken on a whole new meaning for me," Ms Kelly said.

"(It's) my special day, so to speak. It's a day that has a lot more significant meaning to me now."

Rialto's piazza was again transformed into a sea of flowers on Wednesday as part of its two-day Daffodil Day event.

Melburnians wandered in throughout the day to take in the sight of 20,000 daffodils.

Cancer Council Victoria fundraising head Lyrian Fleming-Parsley urged people to donate at events for Daffodil Day, which is on Thursday, to support cancer research.

"Consider giving for all the people who've been affected by a cancer diagnosis, whether that's you, or someone close to you," Ms Fleming-Parsley said.

"Giving money, a bunch of daffodils, your time, a hug, giving hope, that's what Daffodil Day is all about."

Ms Kelly urged people to listen to their bodies, be aware of cancer risks and seek medical attention if they had health concerns.