Prime Minister Jacinda Ardern announced on Monday the government would formally apologise for an infamous part of the nation's history known as the Dawn Raids.

Aupito William Sio recalled the terrifying day during his childhood when police officers holding German shepherd dogs turned up at his family home before dawn and shined flashlights into their faces while his father stood there helpless.

Now the minister for Pacific peoples, Sio and Prime Minister Jacinda Ardern announced on Monday the government would formally apologise for an infamous part of the nation's history known as the Dawn Raids.

It's when Pacific Island people were targeted for deportation in the mid-1970s during aggressive home raids by authorities to find, convict and deport overstayers. The raids often took place very early in the morning or late at night.

Sio became emotional as he and Ardern discussed the apology at a news conference.

We felt as a community that we were invited to come to New Zealand. We responded to the call to fill the labour workforce that was needed, in the same way we responded to the call for soldiers in 1914," Sio said.

But he said the government then turned on the Pasifika community when it felt those workers were no longer needed.

Ardern said that at the time, people who didn't look like white New Zealanders were told they should carry identification to prove they weren't overstayers, and were often randomly stopped in the street, or even at schools or churches. She said Pacific people were often dragged before the courts in their pajamas and without proper representation.

Not only were they targeted, they were targeted using a process and a practice that was really dehumanising, that really terrorised people in their homes," Ardern said.

She said that when computerised immigration records were introduced in 1977, they showed that 40 per cent of overstayers were either British or American, groups that were never targeted for deportation.

The raids, and what they represented, created deep wounds, Ardern said. And while we cannot change our history, we can acknowledge it, and we can seek to right a wrong.

The formal apology will be held at a commemoration event on June 26 in Auckland. Ardern said it's just the third time the government has made such an apology.

The previous apologies were for imposing a entry tax on Chinese immigrants in the 1880s and for introducing the deadly influenza pandemic to Samoa in 1918, which killed more than one-fifth of the population.