"How can we learn from the past if we fail to shine a light on its dark secrets," she said on Wednesday.
Labour leader Jacinda Ardern agrees an inquiry is needed because of repeated requests from victims but also because of ongoing reforms of the state care system.
"How can we make sure that we have a robust system unless we have learned from the past, from that historical abuse. It's the least we can do," she said.
The committee said in a report this week it was "alarmed" by the alleged abuse of as many as 100,000 children - a majority Maori - between the 1950s and 1990s.
It also expressed concern that Maori children remain more likely to be placed in state care than Pakeha children.
The UN committee said an independent commission of inquiry should be immediately set up by the government, with the authority to determine redress, rehabilitation and reparation from victims, including an apology from the government.
It also urged "effective steps" to reduce the number of Maori and Pasifika children in state care, including through whanau first placements for tamariki Maori.
Maori Party co-leader Te Ururoa Flavell backed that recommendation.
"We believe whanau are best placed, with the adequate support, to care for our young," he said.
There have been repeated calls for an inquiry into abuse in state care.
In February the Human Rights Commission backed an open letter from prominent New Zealanders - gaining almost 12,000 signatures - calling for an independent investigation.
Race Relations Commissioner Dame Susan Devoy said earlier this month those who were responsible should be held to account.
The government has repeatedly rejected those calls, with Social Development Minister Anne Tolley maintaining the seven-year Confidential Listening and Advice Service was an inquiry.
She said MSD had received 1370 direct claims of abuse as at last September, and 900 had been settled with an apology and compensation totalling more than $17 million.
