Current controversies facing Sinn Fein have shown that the republican party is “not invincible”, DUP leader Gavin Robinson has said.
Delivering a speech to councillors, Mr Robinson said his party would continue to ask questions of the Sinn Fein leadership.
He also said the Executive Office at Stormont needed to be led “by a minister who can publicly show they understand the importance of safeguarding children”.
Sinn Fein has been criticised for recent weeks for its handling of a number of controversies, including that former press officer Michael McMonagle and ex-senator Niall O Donnghaile.
McMonagle, 42, from Limewood Street, Derry, last month admitted to a series of offences, including attempting to incite a child to engage in sexual activity.
It subsequently emerged that two other press officers, who have since resigned from the party, provided job references for McMonagle after Sinn Fein had suspended him amid police inquiries.
The references enabled McMonagle to get a job with the British Heart Foundation (BHF) in 2022, with the charity unaware of the allegations he was facing.
Then this week, former Sinn Fein senator Mr O Donnghaile revealed he had left the party after sending allegedly inappropriate text messages to a teenager.
Sinn Fein referred that matter to the PSNI and social services last September, but no criminal investigation was undertaken.
Sinn Fein president Mary Lou McDonald has faced criticism for failing to state publicly why the former Belfast lord mayor had resigned when she issued a statement last December praising his contribution and wishing him well for the future.
Mr Robinson said the DUP have “kept Sinn Fein accountable”.
Referring to the McMonagle case, he said: “This is a deeply troubling matter because it concerns the safeguarding of children.
“The gravity of this issue, now compounded by the revelations surrounding O Donnghaile, means Sinn Fein must explain their cover-up and their flagrant disregard for basic safeguarding practices.
“We will continue to hold Michelle O’Neill to account, not for political gain, but because it is the right thing to do.”
He added: “Secondly, as these scandals continue to engulf Sinn Fein, it serves as a reminder that in politics, fortunes can change, and change quickly.”
Mr Robinson added: “Not long ago, Mary Lou was touted as the next Taoiseach.
“Today she is being talked about as the outgoing President of Sinn Fein.
“Colleagues, while the circumstances surrounding Sinn Fein’s difficulties are disturbing, it shows one thing clearly: no party, including Sinn Fein, is invincible.
“Sinn Fein become obsessed about Sinn Fein. Half-truth after half-truth was told to protect the party.
“Let that be a lesson for us all. We are not in politics to advance ourselves or this party, we are in politics because we care about Northern Ireland and its people.”
Mr Robinson said DUP MLAs have asked First Minister Ms O’Neill to return to the Executive Office committee to answer further questions.
He said: “A department charged with responsibility for historical and institutional abuse needs to be led by a minister who can publicly show they understand the importance of safeguarding children.”
The DUP leader said the “safeguarding crisis” within Sinn Fein had been “brewing for years”.
He added: “There is a change of culture that needs to take place.
“As public representatives, we are involved in so many community organisations, there will always been rotten apples who get involved.
“However, it is how we deal with those situations that matters.”
