Cars sold in the Nordic country have a tax assessed depending on the amount of pollution they emit.
“If it is proved that the emissions were higher than they said then it is possible that certain cars were taxed too little,” Finance Minister Magdalena Andersson said on SR public radio on Thursday.
She said Volkswagen has been asked for information to help calculate how much the Swedish state may have lost in tax revenue.
Volkswagen said earlier this week it had sold 225,000 vehicles in Sweden fitted with devices that switch on pollution controls when they detect the car is undergoing testing and then switch off the controls when the car is on the road, allowing it to spew out harmful levels of emissions.
VW Sweden's chief executive, Claes Jerveland, told the TT news agency that the company would look into the matter, noting that so far concerns had been about the motors emitting higher levels of nitrogen oxides rather than carbon dioxide, upon which the Swedish tax is based.
The tax is paid by car buyers, so the Swedish tax authority may have some legal hurdles to clear before sending any bill to Volkswagen.
Sweden's Environment Minister Åsa Romson, who is also Deputy Prime Minister and leader of the Green Party, met with Jerveland on Wednesday.
She told reporters afterwards: “It was a good meeting. They have informed us well and were able to provide an explanation. They also agreed that they would cooperate with Swedish authorities”.
The discussions came after it emerged that a Swedish scientist and environmental campaigner, Per Kågeson, had warned about car makers rigging emissions tests almost two decades ago.
“Tests carried out by the Swedish exhaust emission laboratory Rototest AB reveal that some manufacturers do not take responsibility for the exhaust performance of all or some of their models in situations when the car is driven under conditions not covered by the official European test cycle,” he wrote in a major EU report in 1998.
The world's biggest carmaker by sales, Volkswagen has seen its market value plunge by nearly 40 percent since US authorities accused the company of having fit its cars with software to evade pollution controls.