Villiers defends security veto on secret files tied to Troubles killings in Northern Ireland
The Secretary of State has defended withholding government files for national security reasons.
The contentious issue was raised as Theresa Villiers met with New York law firm O'Dwyer and Bernstein during a two-day visit to the US to promote Northern Ireland.
It is also expected to top the agenda of meetings with senior security figures in Washington.
Speaking from the US, Ms Villiers said: "I had a discussion with the New York lawyers about how we try and resolve the remaining blockages in the way of getting legislation through to set up the legacy bodies under the Stormont House Agreement.
"(It is about) how we provide confidence in relation to how information will be protected, to ensure that everyone is confident that the national security veto would only be exercised where the information really does need to be protected in order to save lives and protect important techniques."
The continuing political row is holding up a £150m package of measures designed to address the toxic legacy of the Troubles, including the establishment of a new Historical Investigations Unit (HIU).
The key logjam relates to the Government's insistence on retaining the right to withhold certain classified files from the public domain.
A number of bereaved families and campaigners want the papers handed over to shine a light on the shadowy world of the security services amid claims of paramilitary collusion and misuse of agents.
But the Government has insisted the release of certain top-secret documents could compromise national security, potentially benefiting Islamic extremists or dissident republicans.
Controversy also surrounds the extent to which state agencies are co-operating with dozens of long-delayed inquests into deaths linked to alleged security force misconduct and collusion.
Ms Villiers said discussions had centred on appeals mechanisms that would give families an opportunity to challenge any decision to withhold documents.
The Government believes the final decision should rest with Northern Ireland's High Court judges, while Sinn Fein wants an international panel of judges to be appointed.
Ms Villiers said: "We need to emphasise that this new, independent police unit will get everything - all the documents which are relevant to the cases which it is investigating which are held by the police, by the MoD and the Government.
"They will have all of it - not redacted, not flagged up. They can see the whole lot and then they can decide whether it is a case where criminal charges are needed and then pass that advice on to the Director of Public Prosecutions - another completely independent office.
"The UK Government is committed fully to disclosure to the HIU, but we do have a duty to protect information which, if it was out in the public domain, could lead to loss of life."
Ms Villiers also indicated the outcome of further discussions on how the US tackles organised crime would be fed back to the new panel tasked with dealing with paramilitary activity.
The purpose of the two-day visit is to brief members of the US administration and senior figures within the Irish-American community on the Fresh Start Agreement and to promote investment in Northern Ireland.
Ms Villiers said there had been a "warm welcome" for the new deal.