New Zealand was among the first of 16 nations to respond to a UN Security Council call for aid, and dispatched two frigates to Korea four days after 135,000 North Korean troops crossed the 38th Parallel.
A troop of 1044 volunteers, known as K-Force, was later formed and arrived in Pusan on New Year's Eve 1950.
They saw combat within three weeks after joining the British 27th Infantry Brigade.
Nearly 6000 New Zealand soldiers fought in the Korean War between 1950 and 1953, and 45 were killed. The last of the Kiwis left Korea in 1957.
"If these Kiwis had not fought in the war, the South Korea we have today may never have been born," said Mr Do, whose father also served in the Korean War.
At the celebration, veterans would be treated to a three-course "gourmet" meal and receive hampers and certificates.
Mr Do said he planned to make it an annual affair "just like Anzac Day" and hoped to involve the wider local Korean community in the future.
Wally Wyatt, who served in K-Force with the 16th Field Regiment, was delighted that Koreans continue to hold those who fought in Korea in such high regard.
"It's just absolutely incredible that even though more than six decades have passed, the Korean community still remember us with such respect ... and continue to honour us like heroes," he said.
"I don't think this has ever happened to any troops in any country ever before, and as far as I'm concerned the Korean people have been absolutely wonderful to us."
Mr Wyatt celebrated his 87th birthday last Thursday with Mr Do and other Korean community leaders, where plans for the May event were finalised.
The immediate past president of the NZ Korean Veterans Association, James Newman, who was also at the lunch, said Koreans treat the vets "like heroes".
Kiwis at war in Korea
3794
served in K-Force
1300
in navy deployment
45
killed
79
wounded
1
taken prisoner
34
buried in Korea
