Liz Truss rejected a plea to restore the abortion ban in Northern Ireland while Rishi Sunak vowed to be "much tougher" on the benefits system in the latest Conservative Party hustings in Belfast.
Responding to an audience member who claimed Westminster had "undemocratically" imposed abortion laws on Northern Ireland, Ms Truss said: "I'm afraid I don't agree with you. We are a United Kingdom and we need all our laws to apply across the United Kingdom. That is what a Union is."
Meanwhile, Mr Sunak promised to "get people off benefits and into work", telling the audience: "If there are hours to do, if there is a job going, people should have to take the job as opposed to just being able to stay on benefits."
He later added: "That is the right thing for them and their families because there is enormous dignity in work and it is fair to everyone, to people who are paying their taxes, who would rightly expect that to be happening."
He continued: "And I want to make sure that I deliver a welfare system that has that outcome."
Both candidates faced tough questions during the hour-long hustings.
A nurse asked Mr Sunak what he is going to do about the NHS, saying in her hospital she saw "two emergency psychiatric beds... mattresses on the floor".
The former chancellor said the NHS is "clearly under strain" but a "priority" for him, and stressed his proposal to charge individuals for missed GP appointments.
Elsewhere, an audience member asked whether Ms Truss's support of Boris Johnson brings into question her "own personal integrity and honesty".
The foreign secretary replied: "I don't agree with that. Boris Johnson has been an excellent prime minister.
"He delivered on Brexit, he delivered on the COVID vaccine and he delivered on standing up to Vladimir Putin and backing the Ukrainians and I'm proud of what he did."
Both candidates were also asked for their position on the Northern Ireland Protocol.
Ms Truss once again referred to herself as a "child of the Union" and told the audience she thinks of the Union as a "family" that she never wants to split up.
She added that the protocol is causing "unfairness" in Northern Ireland, and warned: "Until we sort the issue of the NI Protocol, we're not going to get Stormont back up and running.
"And I've been in discussions with all of the parties in Northern Ireland, I'm determined to make it happen.
"And as we make progress on the Northern Ireland Protocol Bill we will see power-sharing re-established in Northern Ireland, and as well the Belfast Good Friday Agreement re-established."
But Ms Truss said it "might take time" to get the controversial Northern Ireland Protocol Bill through the Lords.
She added that she would not accept an offer from the EU that does not make UK courts the ultimate arbiter, deliver free-flowing trade between Great Britain and Northern Ireland and allow the people of Northern Ireland to benefit from tax decisions.
Meanwhile, Mr Sunak said he would do what is necessary to fix the Northern Ireland Protocol and protect the Union.
"It is clear that the operation of the protocol, as it's currently being enacted, is putting that position at risk - and I will do everything I can as prime minister to fix that," he said.
But the former chancellor also stressed that a negotiated outcome with the EU would be a "much quicker" solution.
Speaking to reporters after the eighth Conservative Party hustings, Mr Sunak renewed his attack on Ms Truss's tax-cutting plans, saying they would not provide much help for low-income households or pensioners.
He said her approach would be a "moral failure of the Conservative government".
"I believe I have the right plan to help everyone in the United Kingdom, support them with the cost of living, particularly the most vulnerable groups in society like those on the lowest incomes and pensioners. But with some help for everyone," he said.
"But what we also must not do is put fuel on the fire of inflation and permanent unfunded tax cuts risk doing exactly that.
"They will significantly increase our borrowing and they risk entrenching high inflation for years to come. That is not the right plan. My plan is the right plan."
There are four more Conservative leadership hustings to go and the winner of the contest, and next PM, will be announced on 5 September.