The Foyle MLA said that the assertion in the House of Commons today that the British Government would take powers at the earliest opportunity.
The remarks were made British Secretary of State Julia Smith after a question from a Labour MP.
Mr Smith said his priority was to get power-sharing to return in Northern Ireland, before the UK is due to leave the EU on October 31.
But he said if that did not happen, then the government needed to have direct powers “at the earliest opportunity”.
Colum Eastwood reacted furiously to the remarks, saying: “Without an Executive, with parliament prorogued and with the 31st October deadline approaching, it is very clear now that the British Government will attempt a power grab against our hard won devolution settlement to make Brexit easier for themselves.
“That cannot be allowed to happen.
“Direct rule by this Tory/DUP government is not acceptable to the SDLP or to the people we represent.
“In the absence of powersharing, the only mechanism that can reflect both traditions on this island in the spirit of the Good Friday Agreement is a form of joint authority with a structured role for the Irish Government.
“I made that clear to the Secretary of State when we met in Belfast.
“Ultimately, however, politicians in Northern Ireland have the power to put an end to the spectre of Direct Rule immediately by reaching a resolution with each other.
“We have worked hard with other parties, particularly the Ulster Unionists and the Alliance Party to forge a consensus on most of the difficult issues preventing the restoration of an Executive.
“It remains our view that reform of the petition of concern provides a path to the resolution of these issues and the restoration of the institutions. That is an immediate imperative,” added the Foyle MLA.