DUP leader Arlene Foster has said Sinn Fein is "isolated and without support" because of the party's "selfish and arrogant" behaviour in relation to the funeral of Bobby Storey.
The veteran republican's funeral last week drew hundreds of onlookers who lined the streets of west Belfast as the cortege passed through.
The PSNI is investigating the funeral for possible breaches of coronavirus regulations.
Deputy First Minister Michelle O'Neill, who was present at the funeral, has apologised for grieving families experiencing more hurt.
She said she did everything within her power to control numbers and marshals were in place but said she would not apologise for attending the funeral of a friend.
In a statement released on Sunday evening, Mrs Foster said that Mrs O'Neill and her colleagues "must take responsibility" for the health regulations being undermined.
"We must not use Sinn Fein as our yardstick on what is right regarding Covid 19 in the days and weeks ahead," the First Minister said.
"To those who are angry and want to show it I ask them to pause and think of their family, friends and neighbours. This virus is still in our communities."
Mrs Foster said the Covid-19 pandemic "transcends religion and politics".
"It makes no difference if you are a unionist or a committed Irish republican, the Covid-19 regulations are for the protection of health and life and must be adhered to.
"We are all frustrated and deeply disappointed by recent events. Sinn Fein stand isolated and without support because of their selfish and arrogant behaviour. The mask of integrity, respect and equality has well and truly slipped."
The DUP leader confirmed she has worked with other party leaders to table a motion in the Northern Ireland Assembly to "send a clear signal that there cannot be toleration for double standards".
She added: "We must focus on steering Northern Ireland through this crisis. While it is deeply frustrating that too much of our time has been diverted to deal with rule breaches by the very people who have helped to make the rules we must never forget that responsible and law abiding people have never used the Sinn Fein ‘standard’ as their yardstick previously and must not do so now.”
A Sinn Fein spokesperson said: “It is unfortunate this matter has divided the Executive.
“Covid 19 is still with us and the public want to see the Executive working together to meet the challenges presented by the health crisis and steering our way to economic recovery.
“We have important work to do and Sinn Fein remains fully committed to power sharing and to the institutions of the Good Friday Agreement.”