The leader of Norway's Conservative party has announced she is forming a rightwing minority government, the first to include the anti-immigration Progress party.

Erna Solberg, whose Conservatives finished second in this month's parliamentary election, will team up with the Progress party, which came third.

The two-party coalition is expected to introduce stricter immigration policies. Many Norwegians have called for a reduction in immigration, and the Progress party has capitalised on that feeling.

Solberg praised her party's co-operation with Progress but left the door open for the two smaller centre-right parties – the Christian Democrats and Liberals – to join the coalition, saying she was eager to work with them, too.

"Now the Conservatives and the Progress party start real negotiations on the government platform. This is the start of a committed relationship," Solberg told reporters in parliament.

In the general election on 9 September, the Conservatives and three centre-right parties won a majority, but only Progress agreed to team up with the Conservatives. Its leader, Siv Jensen, said it hoped to tighten asylum policies, secure more rights for the elderly and reduce inheritance tax.

The new government is scheduled to take office on 14 October. It will replace a moderate but left-leaning coalition led by the Labour party, headed by the outgoing prime minister, Jens Stoltenberg. It has governed Norway for eight years, and Labour will remain the largest party in parliament.

Post-war, rightwing coalitions have often been fractious and fallen apart in Norway, as they did in 1986, 1990 and 2000. If the current coalition doesn't last, the Labour party could quickly reclaim power, as it has three times since 1986.