"Under the direction we've got, they've the best opportunity in two generations to get a foothold in the workforce.
"Under Labour's policy, they are going to pull the rug out from under them," English said.
Labour's policy reflected a view among Opposition parties that the best way to deal with these challenges of growth was to shut down the growth, he said.
"So choke the international education industry, deprive the construction industry of the skills it needs, don't worry about the impact on everything else, because they think New Zealand isn't up to it.
"We simply disagree with that. We think the best way to deal with sustained success is to deal with the challenges of finding the people, making the investments, grappling with the complexities of getting infrastructure and housing in place rather than saying 'let's have a breather and a cup of tea'."
English said the biggest change in the 70,000 figure was fewer New Zealanders leaving and more coming home. The net number would fall but he did not know when.
The Government had yet to decide whether it would go ahead with changes foreshadowed in April, such as limiting workers earning under $49,000 to no more than three years' work.
Little said National had "taken its eye off the ball".
"Labour will get the balance right."
Little said Labour's policy was a response to an "industry" of low-value courses that had developed in New Zealand as a back door for immigration and it was damaging the country's reputation.
"We will end the culture of exploitation and corruption that's grown up to prey on people using this route to come to New Zealand," Little said.
Labour would halt student visas for courses considered to be "low value" and as well, remove the ability to work while studying for students doing courses below bachelor-level unless the work is a course requirement.
Both measures would cut numbers by an estimated 6000 to 10,000, Little said.
The party would also remove the rights to the post-study work visa for graduates from courses below university level unless they have a job offer, a cut of 9000 to 12,000.
We will end the culture of exploitation and corruption that's grown up to prey on people using this route to come to New Zealand.
Little said students who had already been studying in New Zealand under expectations of visas in the current policy would not be affected.
He estimated a further 5000 to 8000 would also be cut by making the New Zealand labour market test tougher for employers before hiring foreigners, and identifying skills shortages by regions and requiring people to live and work where the actual shortages were.
Labour would also create a new "exceptional skills visa" for up to 1000 people - for people with significant experience or qualifications, or who were internationally renowned for their talents - in any field.
English rubbished the so-called "Kiwibuild visa" outlined by Labour to address demand for skilled workers under Labour's policy to build 100,000 houses in 10 years.
Residential construction firms would be able to hire a foreign worker for three years without testing the market for Kiwi tradesmen if they took on an apprentice for every worker hired.
The Kiwibuild visa would be limited to 1500 at any one time, and additional foreign workers would have to be hired under current rules.
"Mate, who thinks you can build 100,000 houses with another 1000 people?" English said to an Australian reporter who questioned it. "It is completely unrealistic."
