Opinion polls suggest a narrow margin between Conservative Prime Minister Erna Solberg and her Labour challenger Jonas Gahr Støre – albeit with numbers slipping for Støre's party as election day approaches.
"It's easier to be blamed for things that are not going well than to get credit for things that go well," noted University of Oslo political science professor Bernt Aardal.
"You can see that the affluence of the Norwegian voters also leads to increased expectations. It is very difficult for any party to fulfil those expectations," he added.
After coming to power in 2013, the government -- made up of the Conservatives and the populist Progress Party -- has had to contend with two serious and simultaneous challenges.
The migrant crisis that swept across Europe saw a record 31,000 people seek asylum in 2015 in Norway, a country of 5.3 million. And the oil industry, the main driver of the Norwegian economy, has been hit since 2014 by the sharpest drop in oil prices in 30 years.
Europe has since shut it borders, Oslo has tightened its immigration policy, and the flow of refugees has dwindled.
Thanks to tax cuts and hefty withdrawals from the country's sovereign wealth fund -- worth almost $1 trillion just 20 years after its first deposit of oil revenues -- Norway has enjoyed a robust return to growth, depriving the opposition of an easy line of attack.
"Now that the Norwegian economy is improving, it's important not to change course," insists 56-year-old Solberg, presenting herself as the safeguard for continued success.
The cherry on the cake: Norway was in March named the happiest country in the world in a respected UN report.
Despite the glowing report card, Støre has accused the right-wing government of making Norway a "colder" place, championing himself as the defender of the less advantaged.
The opposition leader has promised to reverse tax cuts benefiting "the richest" and to beef up the welfare state.
"We have a strong immune defence against social things we've seen in other countries," the 57-year-old Labour leader told AFP.
"But we are not immune, which means that we too have increasing inequality."
Public opinion remains divided.
"We want change," said Silje Krokeide, a medicine postdoc visiting a Labour campaign hut on Oslo's Karl Johans Gate avenue.
"We want more equality, that's important for me. And we also want to take better care of the environment."
Eirik, a 69-year-old entrepreneur, is among those who want the right to stay in power.
"They've reduced taxes, introduced incentives for establishing new businesses, they've built roads and invested in police and health care. I think they've done pretty well."
The election outcome will depend on the scores of smaller parties, as both the Conservatives and Labour depend on their support in parliament to form a government and pass legislation.