The chair of the main opposition National Coalition Party, Petteri Orpo, says his conservative party would be open to a government partnership with the nationalist Finns Party.

Orpo told the tabloid Ilta-Sanomat on Saturday that he expects his party to win the next parliamentary elections in 2023. He said he aims to become prime minister, form a right-leaning government to counteract the policies of the current centre-left cabinet.

Orpo said that cooperation with the Finns Party would largely depend on the party's leadership policies, particularly attitudes towards the European Union. The NCP has traditionally been pro-EU while the Finns Party has been mainly eurosceptic.

"I think cooperation is possible," said Orpo. "However, it would not be easy. It requires trust and a common programme. Again, it depends so much on what kind of leadership the Finns Party chooses and what kind of political line and view of human beings they represent," he said.

In mid-August the Finns Party is to elect a new chair to replace the outgoingJussi Halla-aho, an immigration hardliner. So far MPRiikka Purra appears to be the leading the field of six candidates.

Centre-right parties already dominate Parliament

The two parties are now the largest opposition blocs in Parliament, with 38 seats each, just behind Prime MinisterSanna Marin's Social Democratic Party with 40 seats.

The fourth-place Centre, the number-two government party, has 31 seats, meaning the three centre-right parties already now represent a majority in the 200-seat legislature. Adding the Christian Democrats would give a theoretical right-leaning coalition a solid 112 seats based on the status quo.

A Helsingin Sanomat party support poll published on Tuesday showed the NCP as the nation's largest party with 19.9 percent support.

The next test of the parties' support will be next January's first-ever regional elections, mandated by the 'sote' social and healthcare reform.

Orpo, 51, is just ending a period of sick leave after suffering aheart attack in mid-June. He has served three stints in cabinet, holding the finance, interior and agriculture portfolios as well as two years as deputy prime minister.