An Eritrean man facing deportation has admitted to the double stabbing murder of a mother and son at an Ikea store in Sweden this week, his lawyer said.

"The man has admitted to the two murders," the TT news agency quoted lawyer Per-Ingvar Ekblad as saying.

Swedish media have reported the 36-year-old man had been issued with a deportation order to send him to Italy.

Media reports said the unnamed suspect had met with immigration officials to discuss his case just a day before the attack in the central town of Vasteras.

Footage of the attack shows the man grabbing knives from the kitchenware section and then stabbing two shoppers, a 55-year-old woman and her 28-year-old son, according to the Swedish daily Aftonbladet.

The suspect then stabbed himself in the stomach before being evacuated to the hospital, where he was briefly in a coma.

A second suspect, a 23-year-old Eritrean, was found waiting outside at a bus stop by the furniture store in Vasteras.

Sweden is home to an Eritrean community of about 18,000 immigrants who fled an authoritarian regime and poverty in their home country.

After Syrians, Eritreans are the largest group of asylum seekers in the Nordic country, with more than 4,200 applying for asylum in 2015.

The number of asylum seekers in Sweden is expected to rise significantly in the coming years.

AFP