The Secretary of State has been warned that a failure to secure stable government in Northern Ireland will put up to £1bn of investment projects at risk.
At an event organised by the Institute of Directors in Belfast yesterday, Karen Bradley was grilled by business executives about her plans to fill the power vacuum at Stormont.
Later, Mrs Bradley and Sinn Fein MEP Martina Anderson clashed at the Balmoral Show over Brexit and a border poll.
A High Court ruling on Monday threw doubt on the authority of senior civil servants to take decisions that would normally be the responsibility of ministers.
Mrs Justice Keegan overturned a decision by the permanent secretary in the Department for Infrastructure to give the go-ahead to a controversial incinerator in Mallusk.
At the gathering of business leaders, public affairs consultant David Kerr told Mrs Bradley that "muddling on through" the current crisis was "not an option" and she must move to introduce direct rule to give the business community the security it needed.
"The Belfast power station, the North-South interconnector, Casement Park, the Belfast transport hub and the Dalradian gold mine are projects worth around £1bn, which are at risk without secure government at Stormont," he said.
Mr Kerr told the Belfast Telegraph: "Mrs Bradley stated that Monday's judgment would be appealed and we should wait to see how that goes. Quite frankly, that's not good enough.
"I believe any appeal will fail, and even if successful, those opposed to the incinerator will themselves appeal and the whole process could take over a year.
"We need decisions taken now. Direct rule would be a temporary stopgap until we get power-sharing up and running again at Stormont."
The Institute of Directors' Northern Ireland national director, Kirsty McManus, said: "Karen Bradley was left under no illusion as to the depth of anger and frustration felt in the business community after hearing the frankly expressed views of more than 40 business leaders. The local economy has now endured almost 18 months of political uncertainty following the collapse of the Executive, and maintaining the status quo is simply unacceptable."
Ms McManus stressed that business leaders wanted decisive action taken.
"This week's legal ruling has put at risk more than £1bn of strategic infrastructure projects and cast doubt over billions of pounds worth of projects still in the pipeline across the public and private sector," she said.
"Our members are calling on the Secretary of State to work with her colleagues in Westminster to introduce a mechanism that will allow decisions on these key projects to be taken without fear or hindrance and keep driving the Northern Ireland economy forward."
Speaking at the Balmoral Show, Mrs Bradley said "knee-jerk reactions" to the Mallusk ruling were not the answer.
"This is a specific decision about a specific planning application. We cannot rush into anything - we need to consider what the judge said about that application and make decisions based on that," she added.
"We want to get clarity on this matter as soon as possible. The UK Government is prepared to take steps to ensure there is good governance in Northern Ireland."
Also at the show, the Secretary of State and Ms Anderson clashed over the EU's proposed backstop solution for Northern Ireland.
Mrs Bradley attempted to defuse the situation. "We don't agree with the text that's been put forward by the EU, but let's not talk about that - we are here to enjoy a great show," she said.
But Ms Anderson replied: "We are here to enjoy a brilliant show, but we are not going to be collateral damage and there can be no dilution of our rights."
The Sinn Fein MEP also pushed for a border poll.
When Mrs Bradley tried to end the conversation, Ms Anderson pressed her on legacy funding.
"We are waiting on the Department of Justice," the Secretary of State replied.