According to the new law, which comes into effect on July 1st, a person must now only be suspected of a finable offence for police to have the power to force ISPs to hand over the names, telephone numbers, and IP-addresses of individual subscribers.
The move is meant to make it easier for police to track down individuals suspected of file sharing as well as other copyright infringement crimes online.
The new law replaces regulations stipulating that someone must be suspected of a crime resulting in a prison sentence in order to retrieve user information from internet providers.
"It's a really good change which makes it possible for police to investigate copyright crimes that affect specific individuals," Paul Pintér, the Swedish police's national coordinator for intellectual property crimes, told the TT news agency.
According to Pintér, the new law will make it easier to protect individual copyright holders from having their works pirated or downloaded illegally.
In practice, most investigations into copyright infringements against individuals as well as reports of internet libel are dropped under current regulations.
However, Pintér doesn't expect the new law will lead to a marked increase in the number of reported copyright infringement complaints.
"The complaints we receive today are almost exclusively from copyright holders and there is usually some some substance in their complaints," he said.
The new law also expands police powers to conduct secret wiretapping of electronic communications.
According to the new regulations, a decision to conduct secret wiretaps must be made by a court, but the new also includes a loophole for prosecutors themselves to make interim decisions in cases which are especially pressing.
In addition, police and customs officials will be allowed to make decisions about conducting surveillance for intelligence gathering.
It will also be possible for police and other law enforcement agencies to carry out surveillance even if there are no concrete suspicions against the person in question.
Such general surveillance can only be carried out, however, if the suspected crime carries a minimum sentence of two years in prison and with a court-issued warrant.
Police will also be able be able to require telecom operators to tell them where an individual's telephone may be even if it's not in use.
The measure had the support of the four parties of Sweden's governing centre-right Alliance coalition, as well as the far-right Sweden Democrats.
The Left and Green Parties, however, were opposed.
"It's unacceptable to make changes that make it easier to access our personal information," Left Party MP Jens Holm said in a statement.
"All of our online communication should be as secure as when we write regular letters or talk on the telephone."
According to Holm, the new law "really undermines that security".
"To open the floodgates completely and start to hunt a whole generation of file sharers is not okay," he added.
But Moderate Party MP Ewa Thalén Finné emphasized that the changes made it easier to solve serious crimes.
"It can be threats, stalking, libel or adults who have sexual motives when looking for young people," she told the Dagens Nyheter (DN) newspaper.
Anna Troberg of the Pirate Party, which advocates for a reform of copyright laws, nevertheless expressed concerns what would happen with the information gathered by investigators.
"It's ignorant of the Riksdag to think that these increased powers won't be abused," she said in a statement.
"Private information leaks out of police registries every day. The easier it is to access private information the more information will be leaked out and the more people will be harmed."
The new law was passed in the wake of Sweden's adoption of a controversial EU data retention directive.
According to the legislation, internet service providers will be required to data about clients' telephone, messaging, and internet use for six months.