TL;DR: If you are in the UK or USA, and are planning to give to the Against Malaria Foundation, you can help a Canadian make their donation to a different effective organisation tax deductible. Please let us know in the comments so we can facilitate more of these swaps.
Unfortunately many charities people here may want to give to are not registered charities in Canada or Australia, as becoming registered there is challenging and the number of donors available in those countries is not as large as in the UK or USA.
Tides Canada, a 'fiscal sponsor', used to allow Canadians to make grants to charities in other countries, but for logistical reasons have not offered this service for a while.
However, there is a way Canadians can still make tax deductible donations by 'pairing off' with someone who is planning to give to the Against Malaria Foundation (AMF) in the US or UK. This takes advantage of the fact that AMF is directly tax-deductible in Canada.
- The donor in the UK or US who was going to give to AMF, instead gives to the charity the Canadian wishes to give to.
- The Canadian donor gives the same amount to AMF instead.
I'd be surprised if the Australian government has made a law about what your purpose in doing an otherwise legal act (donating to an Australian charity) is :)
I'm afraid you'd be surprised by large parts of the tax code, which I think can only be described as "perverse."
If you make an agreement "I'll do X if in exchange you do Y," that isn't even a perverse case. Obviously the tax code will treat that differently than doing X without any expectation of reciprocity, and the treatment depends on Y. E.g., if Y is "give a scholarship to my child," then this probably isn't going to be taxed as a donation, even though both X and Y could be deductible in isolation.