It was a welcome coincidence that 1840, the year the Treaty of Waitangi was signed, was also the year Wellington was founded.
"There have been some real highs on the journey, there have been some lows and some stumbles upon the hikoi from 1840 to today."
Speaking after a stirring waiata, the dean of the diplomatic corps, South African High Commissioner Anthony Mongalo, joked he had no choir behind him.
"I think I'll have to recruit the choir who have been signing before," he said.
He extended warm congratulations to the Government and people of New Zealand on the occasion.
Port Nicholson Block Settlement Trust chair Sir Ngatata Love said it was a privilege to host the diplomatic corps.
"Least we forget it was not only at Waitangi that the Treaty was signed, it was right here in our wonderful, smooth beautiful harbour on April 29.
"It took a little while to bring it here but we signed it, 39 of our chiefs signed here, and the descendants are with us here today."
Among those gathered for the celebrations were Rongotai MP Annette King, Wellington Central MP Grant Robertson, and Ministry of Foreign Affairs chief executive John Allen.
The ceremony was followed by kapa haka and cultural performances, bands and comedy.
Today was also the first time the Maori flag has been flown from Wellington Town Hall for Waitangi Day.
In 2009 the tino rangatiratanga flag was recognised by Cabinet as the preferred national Maori flag, after months of consultation in which 80 per cent of more than 1200 submitters came out in favour of the flag.
Ms Wade-Brown earlier said while the flag did not have official status, it was good that it would be flown alongside the New Zealand flag on Waitangi Day.
"Waitangi Day is all about the spirit of mutual respect and nationhood, so we will fly the two flags together. This symbolises and enhances the relationship between the Crown and Maori."
The Governor-General, Lieutenant General Sir Jerry Mateparae, is to host a Waitangi Day garden party at Government House in Wellington this afternoon.