A minor earthquake shook parts of Stockholm early today, sending some scared residents to the streets for safety.

The quake measured about 2.0 on the Richter scale, which is considered only a small tremor, but still very rare for the Stockholm region, said Reynir Bodvarsson, a seismologist at Uppsala University.

"It is very rare that such a big quake happens in the middle of Stockholm," Bodvarsson said.

"Over the past few hundred years, it has only happened a couple of times."

The quake took place in the south-eastern parts of Stockholm shortly after 1am local time, he said.

Some residents initially thought the noise caused by the tremor was a large explosion, and emergency services were flooded with calls from scared locals.

Some residents even left their homes to seek shelter on the street when their windows started shaking, Swedish media reported.

But Bodvarsson said it was unlikely the quake caused any damage to the city.

"If a building was damaged by this, it must have already been in very bad shape," he said.