The terror attacks in Paris had made 20 percent of Danish respondents "more likely" or "much more likely" to vote "yes" in a December 3rd referendum on whether to replace the opt-out with an "opt-in" model similar to the one used by Britain and Ireland, a Megafon poll published on Thursday found.
"For many Danes, terrorist attacks confirm that you should fight for security and that you should use international cooperation to combat terrorist attacks," Johannes Andersen, an associate professor of political science at Aalborg University, told broadcaster TV 2.
Next year the European police agency Europol will become a supra-state agency rather than inter state. The change means that in order to stay on as a member of Europol, Copenhagen must relinquish the exemption on EU justice and home affairs rules it negotiated after Danes rejected the Maastricht Treaty in 1992, and which gives it sovereignty over security legislation.
See also: Europol: What's in it for the Danes?
But the "no" side believes Denmark could still be able to stay inside Europol by negotiating a so-called parallel agreement.
Voters will be asked whether they think Denmark should drop its opt-out on the EU's Justice and Home Affairs policies and instead adopt 22 EU legislative acts.
Uncertainty over the consequences of the vote have left many Danes undecided with less than a week to go.
The latest poll credited the "yes" side with 41 percent of voter sympathies, the "no" side with 38 percent, and 21 percent of those surveyed undecided.
The results were based on interviews with 1,095 people over the past week.
Danes finally adopted the Maastricht Treaty in 1993 after obtaining four opt-outs: the euro, joint defence, judicial cooperation and European citizenship.