Hundreds of Kiwis also took off their shirts to perform a haka in Westminster.
Mr Clements, who has worked in London for four years and says he's not a prude - "I get on the booze myself" - also claimed revellers misbehaved on underground platforms and used "vulgar" language in front of children and elderly people.
Dozens of expats who took part in the pub crawl have emailed nzherald.co.nz or taken to Facebook to dispute Mr Clement's complaints.
Tamsin Smith, who has lived in London for four years and participated in the event each time, said the pub crawl was patriotic and moving.
"Despite the freezing temperatures it is always one of the best days of the year for Kiwis in London.
"Watching the haka in the middle of Parliament Square is quite the sight to behold.
"There will always be a few idiots that ruin the event for the masses, but there is no reason to cancel...the celebrations."
Martin Wackrow said the pub crawl was "a celebration of New Zealand and being a New Zealander".
"The Waitangi Day pub crawl is something Kiwis should be proud of, as no matter where we are we can get together and celebrate New Zealand as being a choice country."
Another participant said she had never felt so patriotic as she had during the Waitangi Day pub crawl.
"It was a day to celebrate being a kiwi, unlike Waitangi back home which has become a day of controversy rather than celebration. Sure there are always a few people who drink a few too many brews, but I didn't see anyone vandalising, fighting, or being disrespectful to locals."
John Key: I celebrated Waitangi Day with my shirt on
Prime Minister John Key said today it was no surprise that New Zealanders in London celebrated Waitangi Day with a few beers and did not believe their antics should be blown out of proportion.
"New Zealanders are pretty well known for having a good time when they're out in London, I'd encourage them to have good behaviour where they can, but going out and celebrating sort of part of what they do when they're in London.''
Reflecting on his own time in London, Mr Key agreed he had also celebrated by "having a couple of beers ... with my shirt on''.
Many others have taken to the event's Facebook page to voice their objections to Mr Clement's criticism.
The pub crawl is one of the highlights of the year for many Kiwis in London, and is attended by thousands.
This year, one of the promoters met the High Commissioner, Derek Leask, and the Metropolitan Police before the event to ensure everything was well organised.
However, Mr Clements, a travel adviser, was appalled at what he saw. "I'm just really ashamed. What was going on was totally disrespectful to New Zealand."
London cops: No real problems reported
A spokesman for the police said no serious incidents had been brought to their attention.
"There is no suggestion they were causing any problems. I'm sure that as disgusting as that [the misbehaviour] would be, it's not the sort of thing we would be made aware of.
"If there was an assault or arrests then, yes, but general 'bad behaviour' is not something we can really take time to go chasing."
He said Mr Clements' claims sounded like "people who have drunk too much".
"As dreadful as it is ... and I wouldn't want to see such a thing, of course ... it sounds like a usual night out in London for people who should know better."
Full complaint by Clements
Last month, Mr Clements wrote on the Facebook page that it was a shame locals and tourists of London would have their first impression of Kiwis performing a haka drunk.
"Have fun embarrassing our country."
Yesterday, he said he first noticed the pub crawlers when he took the Tube into central London.
Drunk Kiwis were running along the platforms, hanging their legs over the sides and yelling obscenities.
"People on the Tube were quite scared," Mr Clements said. "We've just had the London riots and when you see that degree of disorderly people, that does frighten people."
He saw people urinating on a police vehicle, and against the back of Westminster Abbey - in front of two "outraged" elderly volunteer workers.
"A participant abused a landlord of The Red Lion Pub as the participant wanted to use his toilet. The landlord explained the pub was closed due to damage from a number of participants who were in the bar earlier."
Mr Clements said the behaviour was unacceptable. "I'm not an old prude sitting on my laptop writing letters to the High Commissioner; I get on the booze myself. But I just don't want our country to look bad overseas."
He said he did not want to see the pub crawl banned, just more controlled. "It is not a day that should be represented by drunk Kiwis wreaking alcohol-fuelled havoc on the streets of London, and it does nothing for the image of NZ internationally."
A number of others also voiced disgust on Twitter. One wrote: "Group of Kiwi guys really representing NZ well. So f****** wasted on a Waitangi Day pub crawl they just wet themselves outside Subway. Class."
Another wrote: "1000s of drunk Kiwis on the loose."
High Commissioner Leask did not respond to the Herald yesterday but last month he met Clint Heine, who runs the Facebook page offering expats information on the event.
On his blog, Mr Heine wrote they had had "a cup of coffee and a chat".
Last night, he said he received advice "that we try and behave ourselves as much as we can".
Mr Heine also met the police before the crawl and posted on Facebook: "They have let me know that our presence is an event the police look forward to not just observing, but also participating in. Many police are also trying to learn the haka in time ... They have already done all the planning regarding blocking off the area for the haka and have police allocated (many who jumped at being involved)."
