"If you look at the stats, I said 10 per cent of our children do as badly and probably worse than any other western-world counterpart. That is not just controversial scaremongering talk.
"How else could it be phrased other than being dire? That is why the opportunity with this legislation that is before the House is so important, that it is grabbed in a way that both parties are involved so they can build an enduring legacy."
Becroft said the bill would make a massive difference to the lives of deprived children and their families.
"It's going to mean that kids won't go to school without shoes, without a raincoat. They'll be fed, they won't rely on schools to provide lunches and breakfasts. There'll be homes that are warm and dry and don't have mould. They'll be able to easily get to the dentist … we know they'll have access to sufficient housing. That's what it's going to look like on the ground."
In his submission, Becroft said one of the primary measures of child poverty must be either 60 per cent or 50 per cent of the relative, median income, after housing costs.
Speaking to the Herald afterwards, Becroft said he preferred the 60 per cent figure because it would capture more disadvantaged children – from around 220,000 at 50 per cent to 290,000 children.
"It might be that the 60 per cent relative figure after housing costs is too aspirational. As we said in our submission I wouldn't die in a ditch over one or the other. If pushed, the preference for the 60 would include every possible child who would be considered to be in income disadvantage."
Prime Minister Jacinda Ardern and National Party leader Simon Bridges met last week as Ardern sought cross-party support for the legislation.
National supported the legislation at the first reading but wants three amendments, including continuing with National's "social investment" approach, which uses detailed data to identify and target at-risk families for support. It also wanted Better Public Services targets reinstated.
Labour has scrapped National's mechanism of such targets but has set its own three- and 10-year targets for reducing child poverty.
The 10-year target is to halve the number of children living in poverty.
The Child Poverty Reduction Bill's second reading is expected in August.