The move follows last week's ruling by the Constitutional Court that the work of a council studying the archives of Romania's secret police was illegal.
That ruling annulled tens of thousands of investigations into people standing for public office - from the president to the lowliest local official.
It prompted protests demanding that the work of the council should continue.
The CNSAS council to study the archives of Romania's notorious secret police, the Securitate, was set up under a 1999 law and is investigating some two million files.
More than 400 people have been exposed as former Securitate officers and 68 as collaborators.
But the Constitutional Court ruled last week that the council was unconstitutional, functioning as prosecutor, judge and court of appeal at the same time.
The ruling led to street protests by civic groups.
The government then stepped in, issuing the emergency decree to enable the investigations to continue.
Two changes were made to the original 1999 law to allow the council to continue functioning, the BBC's Central Europe reporter Nick Thorpe says.
From now on appeals against council rulings can be made to ordinary courts rather than to the council itself, and the council may only consider each case once, not twice as before.