Legislation to hike the price of cigarettes to about $30 a pack by 2020 has passed - despite being condemned by New Zealand First and Act.
Act's support agreement with National meant the party's leader, David Seymour, voted for the change because it was a Budget measure.
But he said the 15 per cent of adult New Zealanders who smoke each day - about 550,000 people - would be hit hard, and estimates of those who would quit were overstated.
Instead, many would sacrifice spending on food and other essentials, and their children would suffer, Mr Seymour said.
"This policy will take tobacco tax on the average smoker from $2800 per year up to $3800, and that is not an enlightened policy, it is a highly regressive tax and the costs imposed in terms of poverty and deprivation on the people most in need far outweigh any possible benefits."