He said a Ministry of Defence team was being set up to advise how ex-service members could be shielded amid growing pressure to stop repeated attempts to prosecute ex-soldiers over actions in Northern Ireland decades ago.
Mr Williamson told the House of Commons: “I understand concerns over whether serving and former personnel are receiving the legal protection and certainty that they deserve.
“I have established a dedicated team within the Ministry of Defence to consider this issue and to advise on the way forward.
“We are very keen to find a longterm solution to help all service personnel from conflicts, not just Northern Ireland but in terms of Afghanistan and Iraq, in making sure that vexatious claims are eliminated.
“The reason we are setting up this team is to look at the different options.”
Northern Ireland Secretary Karen Bradley has launched a consultation into dealing with the region’s toxic conflict legacy.
But veterans and campaigners are angry it does not explicitly propose an amnesty for former soldiers.
Ms Bradley’s department says such protection could not realistically be introduced without offering alleged terrorists similar terms, which would be unacceptable.
Conservative former minister Sir Henry Bellingham urged Mr Williamson to consider a statute of limitations for all conflicts.
He cited the case of former Regimental Corporal Major Dennis Hutchings, 77, who was recently arrested and charged with attempted murder over a shooting in County Tyrone in 1974, despite being cleared of wrongdoing by the Ministry of Defence in that year.
Tory MP and former Army officer Bob Stewart said alleged terrorists were given “letters of comfort” under the Good Friday peace deal, promising them immunity from prosecution.
He asked: “Can’t we give a letter of comfort to our soldiers?”
Meanwhile, Tory former defence secretary Sir Michael Fallon is expected to announce that he is seeking to amend Northern Ireland Budget laws to stop public money being used to fund historical prosecutions of former soldiers.
He is expected to tell MPs: “It’s morally wrong that those who served to keep us safe from terrorism should be threatened with possible imprisonment in respect of allegations made 30 or 40 years ago which have already been investigated, while some of the terrorists have been guaranteed immunity from prosecution through comfort letters.
“We need to stop hounding our own brave servicemen and women and stop it now.”