Waikato Mongrel Mob say police blatantly tried to intimidate its members after they stormed a party to celebrate a trio of birthdays, including that of their leader Sonny Fatu.

Mob spokeswoman Louise Hutchinson counted 14 police vehicles - including several vans, a paddy wagon and marked and unmarked police cars - and about 40 officers in and around the outside of the Irondog building on Bandon St, Frankton on Saturday night.

The police entered the premise with a search warrant under the Sale of Liquor Act but Hutchinson said it was a BYO event and no alcohol was being sold.

"How shameful is it of the Waikato police to send in dozens of officers, in a blatant effort to intimidate our members and what seemed apparent to use heavy handed tactics to try and provoke some type of disturbance in a private establishment, which also included children, rangatahi and wahine," she told the Herald.

However, a police spokesperson said prior to the warrant being executed "there were reports of disorder offences involving gang members that were present at the party, including blocking off roads, burnouts and vehicles and occupants doing laps of the central city".

Hutchinson said the Waikato Mongrel Mob was a "high level of organisation" which paid a high level of regard to its members especially around drinking.

One of many Waikato police officers inside the Irondog premises during a combined Mongrel Mob birthday party on Saturday night.

She said she had told police on several occasions that the party was happening and had even asked the Waikato gang liaison officer if there were any planned visits by police to the party but was told no.

"It seems everyone bar the Waikato Police are aware of the kaupapa that Sonny Fatu leads from the front about, that is to be positive, constructive and productive members of the Hamilton/Waikato community.

"The event was a 40th birthday party for twins as well as the celebration of Sonny's 15-year-old son. There was no alcohol for sale it was BYO.

"They had every opportunity to engage with us as an organisation over their concerns regard the sale of alcohol, which were unfounded, but yet they continued on with their heavy handed and hugely expensive approach with taxpayer dollars, and came up with nothing."

Police spent an hour at the party - arriving 30 minutes after it started - getting people's details and checking to see if any alcohol was being sold.

Hutchinson said she was told a liquor licence would have cost $80.

"So was this all over potentially $80? Or was this about the Waikato Police and the NZ Police force usurping their power?"

As for why a convoy of loud motorbikes and vehicles which did a loop of Hamilton's main street about 8.30pm on Saturday night, Hutchinson said it was to meet out of town visitors and to escort them back to Bandon St.

The police spokesperson confirmed the warrant was in relation to the alleged illegal sale and supply of alcohol.

Police officers are lined up beside the paddy wagon just minutes before the operation is finished and staff return back to the Hamilton central police station.

"A large number of gang and organised crime members were present at the address, including a variety of different chapters of the Mongrel Mob along with other gangs."

Police also wanted to stop members from any further disorder before it escalated.

"Police will respond to incidents reported to us. Our job is to ensure our communities are safe and free from crime, violence and drugs."

As for the amount of resources used, the spokesperson said as per any risk assessment, "police utilised enough resources to ensure that our staff and people present at any event that is being policed are safe and feel safe along with ensuring the safety of the public."

"Alcohol is a major driver of crime which can lead to violence and disorder amongst not only gang members but also the general public.

"There were minimal minor arrests for disorder and unrelated events. Evidence was also gathered in relation to the illegal sale and supply of alcohol."