The DUP has angrily hit back over Sinn Fein claims it is willing "to do David Cameron's bidding" over welfare reform.
On a new blog, MLA Barry McElduff argued the DUP did not want to challenge the Government over the changes.
The DUP and Sinn Fein have been at loggerheads for more than a year, and now the Treasury has initiated cuts to the province's block grant to recoup the savings it calculates the reforms should have achieved.
On his new blog, Mr McElduff commented: "...fair play to my colleagues in Sinn Fein who are doing everything they can to block the introduction of the worst elements of the Tory welfare cuts agenda. It is not always understood why there are problems at Executive level in Stormont.
"Usually, it is because Sinn Fein is standing up for the most vulnerable and the most disadvantaged in our society and others, notably the DUP, want to do David Cameron's bidding without any challenge."
But DUP Upper Bann MP David Simpson hit back: "Barry McElduff should explain the Sinn Fein cuts. £13m was lost to the Northern Ireland budget for jobs, education, policing and health last year due to SF's irresponsible approach to welfare.
"We will have an £87m penalty due this year and £114m penalty due next year. Sinn Fein needs to explain its cuts at a time when budgets are already tight. SF is hurting the vulnerable."