"This is a time for reflection and understanding. It's also a time for healing and hope, not just here in Wellington, but in all our communities across the motu."
Speaker of the House Trevor Mallard and Te Ātiawa Taranaki held the ceremony.
Mallard said it was another step towards reopening the grounds to the community and public.
"The people of Wellington and those who live and work around Parliament have felt the impact of the occupation, and I hope this morning's ceremony will bring us all a step closer to feeling more settled and welcomed back into the parliamentary grounds and surrounding areas."
The lawns and play space remain closed, but members of the public can once again use the paths around Parliament's buildings as a thoroughfare.
Representatives from police, parliamentary security, and politicians are among those gathered including Labour's Kelvin Davis, Meka Whaitiri and Willie Jackson and National MP Shane Reti.
Deputy Prime Minister Grant Robertson acknowledged the local iwi and Rahui Papa from the Kingitanga.
He said the three weeks of the protest were the hardest he has known as a politician "and I'm in the Labour Party".
Some students from nearby schools are also at the event - Robertson noted they were cut off from their schools during the protest. He said the hardest thing he had watched was students being escorted from the railway station to school by security guards, some being spat on.
"No New Zealand school children should have to go through that. Welcome back."
Police Commissioner Andrew Coster said he was immensely proud of all the police who helped to restore order.
"There's been a lot of conversation inside the organisation and I've been in contact with staff who were injured. They're all incredibly proud of how we came together and resolve the situation and the most common comment I've heard was 'that was the most amazing day of my career'."
He said a lot of serious criminal offences were committed on the final day of protest.
"Those investigations are ongoing and we will see people in front of the courts. In the end that was about fighting with police and not a protest."