"They will be clients who we want to help to prevent from being long-term unemployed."
Under a so-called "investment approach", her agency is now required to focus its efforts on people who are capable of working but are likely to stay on welfare the longest unless they get help.
A valuation of taxpayers' long-term liability for current beneficiaries last year found that sick and disabled people accounted for 54 per cent of the total liability of the four main working-age benefits, compared with 38 per cent for sole parents and just 8 per cent for the unemployed.
Three-quarters of the 49,000 who have been on unemployment benefit have been on welfare less than a year and are expected to find new jobs again under their own steam as the economy recovers.
They will be the bulk of 40,000 people who are being placed in a new "work-search" stream, with a "one-to-many" service of one Work and Income case manager for every 210-215 people.
A much larger group of 255,000 people are staying in a "general case management" stream focused on simply paying out benefits because they will not have to look for work.
They include 83,000 people who were on the old invalid's benefit, now called the Supported Living Payment, plus sole parents with young children and 70,000 people who are already working and only receive top-ups such as accommodation supplement.
Neither the "work-search" nor "general case management" streams will get personalised case managers, who were abolished across Work and Income in 2010 to cut costs.
People in those streams will still have to make appointments through a call centre and see the next available case manager.
But Ms Power says the 85,000 in intensive case management will get "one-to-one" service from the agency's most experienced case managers.
"The case-load ratios in there will be about 1:100," she says.
"If you are on the intensive case management stream, those with focus case managers, of which I believe there are 760 of them, will be talking to the clients that they'll be working with about how they will be working with them, the sorts of expectations they have of each other, and really engaging with them to say, 'How can we help you?"'
Asked if intensive case managers would give clients their direct phone lines, as they did before 2010, she says: "Ooh, as far as I know, as far as I'm concerned they should do that."
Asked whether clients would be able to text them on mobile phones at all hours, as young people can to contact their "youth coaches" in a service that was contracted out last August, she says: "I don't know whether our staff want to be working any time of the day or night."
She says the one-to-one service has already operated on a pilot basis with 10,000 clients in 24 locations since last October. The agency says 3516 of those clients have found jobs.
A small part of the new service is being contracted out. Contractors are due to be chosen on July 23 to help 1000 sole parents and 1000 beneficiaries with mental health conditions to find work.
But Work and Income will work directly with the 85,000 in its intensive case management stream.
Although Ms Power says the agency is unlikely to adopt the term "coach", the vision requires transforming its role from "gatekeeper", deciding who gets financial benefits, to something much more like the youth service "coaches".
So far there is little sign of this change in one of the 24 places where the new approach has been tested, Papakura.
"Ninety per cent of the officers are not very kind," says one man on an invalid's benefit who had cancer surgery this month.
"Some young officers are very proud and they think we are like beggars. When I am going to Work and Income I am actually praying to God because I don't know what will happen.
"When we call them they are not replying. Sometimes we are upset and confused but we don't know what to do because they are not calling back."
Greg Nigro, another invalid's beneficiary, says: "You are made to feel like dirt."
In principle, people on Supported Living Payment (SLP) will not have to look for work because the criteria for getting it remain the same as for the old invalid's benefit - being unable to work 15 hours a week for at least the next two years.
But the official SLP pamphlet says: "We may ask some people on SLP to do a self-assessment to tell us about the sort of work they think they might be able to do and how we could help them to achieve that."
Work and Income says most people going on to Jobseeker Support for health reasons will also have to complete the new four-page self-assessment questionnaire, which asks people about their sports, hobbies, volunteering and work experience, the kinds of jobs they would like to do and the extra support they would need to do those jobs.
Work and Income says it "will use the information provided by the person in their application form and self-assessment, and the medical certificate provided by their doctor, to make a decision about the benefit and associated work obligations (full-time, part-time or deferred) someone will have, and to stream people to the appropriate level of service".
