A 73-year-old South African has become the oldest person to swim across the English Channel but a Brisbane grandmother hopes to reclaim the title for Australia.

A 73-year-old South African has become the oldest person ever to swim across the English Channel, beating the record set by Bondi local Cyril Baldock less than three weeks ago.

Heart surgeon Otto Thaning said he wanted to show what older people could do if they took care of their health.

“My wish was basically to promote the idea that people over the age of 70 can do things like this if they look after themselves and work hard,” Thaning told the BBC.

The South African took the title of oldest person to cross the Channel from Baldock who was 70 years and nine months when he swam from Dover in England to Cap Gris Nez in France on August 20.

But a Brisbane grandmother could reclaim the record for Australia in the coming days.

Irene Keel, just a month shy of turning 74, is in Dover waiting for the right conditions to make her own attempt at crossing the Channel.

She told AAP on Sunday she believes she’s seven months older than Thaning.

Keel, who started swimming aged 50 due to a back problem, has previously swum the famous stretch of water three times with relay teams.