Sweden plans to scrap its 25-year statute of limitations on murder, just over a year before the statute expires on the unsolved 1986 killing of Swedish prime minister Olof Palme.

"The possibility of investigating old crimes has improved, thanks among other things to DNA technology," Swedish Justice Minister Beatrice Ask said in a statement.

"There is today a sterner view than previously on some serious crimes, such as murder. Even internationally, the trend has been to abolish the statute of limitations on the most serious international crimes," she added.

The Swedish centre-right government said the law would be applied to murder, manslaughter, genocide and terrorism crimes, all of which are crimes that carry a life sentence.

The law would be applied retroactively -- and therefore to Palme's murder.

Under current laws, the statute of limitations on his killing would expire in 2011.

Palme was strolling down a busy Stockholm street on the night of February 28, 1986 with his wife Lisbet when an unidentified assailant gunned him down.

Despite tens of thousands of tips and leads in the almost 24 years since the crime, the murder has never been solved, and the weapon, a .357 Magnum revolver, has never been found.

The government's proposal has been sent to the Council on Legislation for a judicial preview.

Once presented to parliament, it should pass with ease since the government holds a majority in the assembly.

The government said it expected the law to enter into force on July 1, 2010.