Theresa Villiers has called for rapid progress from politicians as she begins a new term as Northern Ireland Secretary.
Ms Villiers said it was time to get on with the implementation of the Stormont House Agreement which brought an end to months of deadlock in the powersharing government in Belfast.
She has pledged to transfer powers over corporation tax from London to Northern Ireland if the deal is adhered to - potentially creating large numbers of new jobs if a lower rate is set.
Negotiations are due to take place after Sinn Fein said it could not accept welfare reform provisions of the agreement.
Ms Villiers said: "It is essential that we make early and rapid progress on implementing the Stormont House Agreement.
"The Agreement has the potential to deliver significant steps forward for Northern Ireland across a range of issues, including the functioning of the Executive, dealing with the past and building a stronger economy. It is vital therefore that we urgently resolve the issue of welfare reform.
"I am looking forward to working with the Executive and the wider community as we seek to build a stable, peaceful and prosperous Northern Ireland where politics works, the economy grows and society is stronger and more cohesive."
Sinn Fein Deputy First Minister Martin McGuinness claimed the Tories could introduce cuts worth millions of pounds.
He told assembly members at Stormont: "The challenge that poses for all the devolved administrations is very clear for everyone. The SNP are now majoring on the issue of austerity. All of us are going to be affected by this, not just the people on welfare."
The SNP is the third largest party at Westminster with 56 MPs.
Mr McGuinness added: "The £12 billion (welfare cuts) which the Treasury ministers have refused to answer in relation to where they actually fall, that needs to be considered, we need to hear what the plans are."
He said he expected £18 million worth of other cuts.
The Mid Ulster assembly member called on all public representatives and ministers to work together and claimed MPs elected from Northern Ireland and sitting at Westminster would not make any difference to the view of the Conservatives.
"What will make a difference will be a united front from all the parties in our administration, making united cause.
"The hope certainly for all of us has to be that what is happening in Scotland will have an impact on the Conservative Government."
He added the Conservatives should recognise the importance of supporting a society emerging from conflict.
More talks are due on outstanding aspects of the Stormont House Agreement this week.
Sinn Fein is to seek an extra £1.5 billion spending power for Northern Ireland in negotiations with the new British government.
That equates to the amount Stormont power-sharing ministers have lost over the course of the last parliament, the party has said.
First Minister Peter Robinson, leader of Northern Ireland's largest party the DUP, has said republicans need to fulfil their commitment to the Stormont House Agreement.
It was signed between the five main Northern Ireland parties in December, and Prime Minister David Cameron said extra "firepower" had been agreed for the devolved administration.
Key to that was implementing welfare reform, but Sinn Fein said not enough money was available to protect the disabled and others from benefits cuts.
Ms Villiers has made the devolution of powers like corporation tax - ministers hope to lower it to compete for foreign investment with the Republic of Ireland - dependent upon welfare changes.
The ministerial executive's public spending budget is due to be reviewed next month.