Zelezny achieved the mark with his first throw on South African soil at the Sanlam Super athletics meeting in the northern town of Pietersburg.
The throw easily outstripped his Barcelona winning distance of 89.66m and also beat his own previous best of 94.74m which was recorded in Oslo last July but ruled illegal because of the javelin's carbon-fibre shell.
'Yes, I am very happy,' said Zelezny, before explaining his mission in South Africa, 'but this is training.'
It is the first world athletics record set in South Africa since the country's readmission to international competition. The last South African-set record was John van Reenen's 68.48m in the discus in Stellenbosch in 1974.Reuse content