NI minister 'vigilant for unjust welfare reform cuts'
Social Development Minister Alex Attwood has raised concerns about planned welfare changes.
PM David Cameron said the "refreshingly radical" reforms would mean people would always be better off in work.
He said changes would cost more upfront but would be phased in, with other welfare savings made to cover the cost.
Mr Attwood said he "would be blunt about what will not work, acknowledge what might and identify what are unjust cuts masquerading as reform".
The SDLP assembly member said he had three major concerns which he would raise with government ministers in London.
"First, will the high upfront costs of benefit change be paid out of upfront severe benefit reductions?
"Second, will benefit changes just end as a blunt instrument hitting those in need, as has been the case with the Chancellor's emergency June budget?
"Third, will there be any acknowledgement of the conditions in Northern Ireland, where benefit changes to get people into work could end up as a dead end because of the lack of jobs, given the recession here until 2012 at least?"
Mr Cameron told the BBC's Andrew Marr Show on Sunday that the proposed changes, to bring welfare benefits for the unemployed and low-paid together under a new "universal credit" system, were the most far-reaching for more than 60 years.
The prime minister declined to confirm or deny reports that these cuts would include ending some universal benefits such as Child Benefit paid for those over the age of 16.
"On the one hand we've got to ask are there some elements of universal benefits that are no longer affordable?
"But on the other hand, let's look at the issues of dependency, where we've trapped people in poverty through the extent of welfare that they have," he added.
At the moment, parents are paid £20.30 a week for the eldest child and £13.40 for subsequent children, with payments continuing until the age of 19 for those in full-time education.
In the longer term - according to reports the changes could be phased in over 10 years - the move to a single welfare payments system would save "huge amounts of money" because there would be less error, fraud and waste, Mr Cameron said.
Welfare reform has been seen as key to plans to cut the UK's deficit, but has been the source of reported tension between the Treasury and Work and Pensions Secretary Iain Duncan Smith.