Military experts said Sweden was probably unable to defend itself on its own in the event of an invasion, in a report published Thursday, saying the armed forces lacked necessary resources.

"Can We Defend Ourselves For a Week?" the Royal Swedish Academy of War Sciences asked in the title of its report.

Sweden is not a member of NATO and has a policy of military non-alliance, though it does participate in the Alliance's Partnership for Peace programme.

The report echoed comments made by Sweden's chief of the armed forces Sverker Goeranson in the media in early January, when he said the Scandinavian country would only be able to hold off an attack for "about a week", following repeated cuts to the defence budget.

Goeranson has been on sick leave for exhaustion since making his remarks.

The Academy's study, conducted in 2011 and 2012, supported his analysis of the situation.

"We think the military does not have a credible ability to defend all of Sweden ... In the event of a possible attack against Sweden, we would always need help from abroad," it wrote.

"We think that the authorities should rapidly carry out a study on the conditions and possibilities of obtaining such assistance so that any potential crisis in the Baltic region can quickly be resolved, thereby avoiding any act of war from being undertaken," it said.

The Academy highlighted a lack of personnel, logistic capacity to supply troops, anti-air defence, anti-tank weapons and aircraft. It singled out the Baltic Sea island of Gotland, located between southern Sweden and Latvia, as particularly strategic and vulnerable.

However, it said "the military's capacity for international operations is good, even excellent."

In Sweden's 2013 budget, the defence allowance accounts for only 1.2 percent of gross domestic product, a level that has been in continuous decline. In 2007, it was 1.5 percent.