The main challengers to the Stoltenberg-led coalition were the Progress Party of right-wing populist Siv Jensen and the conservative party led by Erna Solberg.

Solberg was credited with running a strong campaign, and saw her party gain some 3 percentage points to 17 percent.

'We have won the elections,' Solberg said as her party gained seven seats, but said she had also hoped for a new government.

However, the smaller Christian Democrats and Liberal Party lost support compared to 2005. Liberal Party leader Lars Sponheim said he would step down in the spring. Both parties expressed reservations against the Progress Party's calls for tighter immigration rules.

'I am proud the Progress Party made its best result ever,' Jensen said after the party secured its position as second strongest partyin Parliament with 40 seats, a gain of two.

She campaigned on tighter immigration rules and spending more of Norway's oil wealth.

Main election issues included the size of social expenditures, especially on education, and whether oil and gas drilling should be allowed in sensitive areas off the north-western coast.