David Cameron was answering a question in the House of Commons from Democratic Unionist Party MP Nigel Dodds.
Mr Dodds said legacy funding provided in the Fresh Start deal could help relieve financial pressures on police.
He also said no-one should be allowed to rewrite the history of the Troubles.
Mr Cameron said he would consider Mr Dodds's arguments, adding: "We need to make sure the policing of Northern Ireland continues to be properly resourced, not least because we continue to face a terrorist threat today."
The government has set aside a total of Â£150m for bodies that are to investigate Troubles-related cases.
But a failure by Stormont politicians to agree on how best to deal with the past has meant the money is on hold.
Earlier this month, the Northern Ireland Office said no more cash would be made available to deal with police investigations into crimes of the past.
The prime minister has said he will "look carefully" at requests for money set aside for dealing with legacy cases to be released to Northern Ireland's police force.