Bill Duff of Belfast wrote to say British financial support for the rebuild would show the people of New Zealand that the UK had not forgotten them.
"A fraction of our money from our overseas aid budget would rebuild a new earthquake-resistant cathedral and demonstrate that the British remember their friends."
Patrick Thomas of Over Wallop Hampshire agreed: "Britain can surely contribute towards the restoration of this site, which would mirror much of what has been creditable in British life."
The decision by the Anglican Diocese to demolish the cathedral was driven by financial concerns.
Bishop Victoria Matthews said it would cost more than $100 million to fix the historic building - although experts disputed the reconstruction figure, putting it closer to $20 million.
The money issue could be addressed, suggested some Britons, by helping to reciprocate New Zealand's generous post World War II donations.
Dudley Reading felt:"After the Second World War, New Zealand (which had a population of just over two million) donated over £10 million towards the reconstruction of war-ravaged Britain.
"Might this be the hour to show a measure of gratitude for that small country's unflinching support for Britain in its time of need, and to come forward in a reciprocal manner in the reconstruction of Christchurch?"
Christchurch City councillor Aaron Keown said the support is a brilliant gesture which demonstrates the significance of what Christchurch is about to lose.
"The Christchurch Cathedral is is our 'Eiffel Tower' and should be treated with the same respect. The offer from our brothers in the UK speaks volumes for the Cathedral's world heritage status."