A DUP MP has said Sinn Fein must get back to government to prevent young people from being sucked into the 'political vacuum' created by the Stormont stalemate.
Gregory Campbell was speaking after trouble flared at an unauthorised dissident republican parade in Londonderry on Monday.
Youths pelted police officers with petrol bombs, bricks, bottles and masonry to clear a path for masked men to parade through the streets of the Creggan estate.
Sinn Fein's Michelle O'Neill took to Twitter to condemn the violence, saying: "Everyone has a right to remember their dead in a respectful and dignified way.
"Scenes from Derry today are very disturbing. Masked individuals causing disturbance, youths throwing petrol bombs etc is far from dignified. Those responsible should be brought before the law."
Mr Campbell, the DUP MP for East Londonderry, said Sinn Fein must now follow up those words by supporting arrests.
He also referred to Ms O'Neill's presence at republican commemorations, including an event last year to honour four IRA men shot dead by the SAS in Clonoe, near Coalisland, in 1992.
"I think that statement is proper and appropriate," Mr Campbell said.
"Some would say she shouldn't then go along and commemorate people who did similar things 20 or 30 years ago. That is where I think some will draw double standards.
"Her statement is good and accurate as it relates to yesterday.
"But unfortunately people like her wouldn't have said the same thing 30 years ago, whenever the organisation that she is affiliated to were doing similar things.
"But that is the past, she has said what she has now. There needs to be action put to those words. When the police follow up and hopefully make arrests, that needs to be supported by all the elected representatives."
Mr Campbell said that political uncertainty had created a vacuum which was being manipulated by some organisations.
He said Sinn Fein needed to get back to government.
"It is obviously a case that when a political vacuum is allowed to emerge then people will try to fill that vacuum," Mr Campbell added.
"I do think Sinn Fein could be doing more. If they were saying to all the political parties and their own community that they are going to get government up and running again to ensure that there is no vacuum created, we would welcome that. We do need to move forward."
However, Sinn Fein MLA Karen Mullan said the blame for the impasse lay with the DUP.
"Gregory Campbell's DUP collapsed the talks process rather than restore political institutions on the basis of equality and rights and which can deliver for all," she said.
"The DUP has continued to deny citizens rights, language rights, marriage rights and the right to a coroner's inquest which are enjoyed by citizens everywhere else in these islands.
"The institutions could be restored tomorrow but they must be based on equality, respect and integrity. This is the only sustainable way government in the north can function."
On the parade violence, Mr Campbell said that the PSNI must move swiftly on those who broke the law on Monday.
He said the main speaker at the event, former prisoner and Saoradh member Stephen Murney, should be arrested over incitement to hatred after his speech quoted Karl Marx, saying that republicans 'would make no excuses for the terror'.
"If he used that quote about the terror, that is a very specific reference to either him or the organisation he represents threatening the community with terror," Mr Campbell said.
Calling for a firm police response to Monday's events, he added: "What the police must not do is say that the day is over - no application was made for the parade route and there were petrol bombs, stones and bricks thrown at officers - therefore it is business as usual."
PSNI Chief Inspector Ivor Morton said: "We will review all of the video footage captured yesterday and anyone who engaged in attacking police or any other actions that are unlawful or detrimental to community safety can expect to face consequences through the criminal justice system."
See Malachi O'Doherty, page 23