According to Redcross website:
Alternatively, one can also donate online via DBS website @ https://internet-banking.dbs.com.sg
If you do not have a DBS/POSB internet banking account, you can also do it at any of the DBS/POSB ATMs.
Or, you can organise a collection at your workplace and send someone down to donate the entire amount collected. That's what my workplace is doing now.