Auckland Transport spokesman Mark Hannan told crowds to "have fun...but be patient and take care if you're driving in".
Auckland Transport is one of the organisations who are participating in the parade for the first time.
Police's parade operation commander Inspector Ross Barnaby encouraged people to have patience and to look out for each other.
"Crowds are starting to build in the area and we hope that everyone has a fantastic evening. Please look after your belongings, remember the liquor ban in the area, and look out for your friends," he said.
Labelled the 'largest and loudest carnival of diversity' in this country by organisers, including producer Shaughan Woodcock, crowds are expected to top 250,000 people.
The parade will feature more than 50 participants who will parade the north end of Ponsonby Rd, near Tole St, toward Western Park at the Karangahape Rd end.
Among the floats will be a one-of-a-kind police patrol car donning rainbow colours, a first-ever New Zealand Rugby float, and a rainbow cement mixer truck from Fletcher Building.
The parade prides itself on celebrating New Zealand's rainbow communities including people identifying as gay, lesbian, bisexual and transgender.
Ardern, who typically participates in the parade, previously told the Herald she was "enormously proud" that it's an annual event.
"The fact we live in a country where we shut down the streets to celebrate diversity, and that we can tell a generation of young people that they live in a place that is inclusive and supportive of who they are, is something I hope we keep doing. I know I will."
The parade is the culmination of the Auckland Pride Festival which showcased weeks of extravaganzas including 80 events involving local and international artists.
