Speaking ahead of addressing a major anti-austerity rally in London tomorrow, Saturday, Mr McGuinness said.
“The policies being pursued by a cabinet of millionaires at Westminster are an ideological attack on the working class and are having a devastating impact on the most vulnerable in our society and on our public services.
“The austerity policies of the British government have brought our devolved institutions to the brink of collapse. The real crisis for our Assembly and Executive is Tory cuts.
“The slashing of £1.5 billion from our block grant by the Tories is severely impacting the Executive’s ability to deliver public services.
“Sinn Féin have been absolutely clear in our opposition to Tory cuts and we are encouraging others to join together to present a united voice against austerity. We have blocked their welfare cuts, the bedroom tax and the targeting of people with disabilities.
“Sinn Fein will continue to resist the anti-working class agenda of the British Tory party,” he added.