By Essi Lehto and Anne Kauranen

HELSINKI (Reuters) - Finland's right-wing government has asked parliament to extend until the end of 2026 a law that allows it to reject asylum applications from migrants crossing its closed eastern border with Russia and to send them back, it said on Thursday.

NATO member Finland has accused Russia of weaponising migration by encouraging migrants from third countries to cross their shared border, an assertion the Kremlin has repeatedly denied.

"The threat of instrumentalised migration at Finland's eastern border remains high and unpredictable," Interior Minister Mari Rantanen said in a statement, adding the situation at the border was tense but stable.

While Finland's non-discrimination ombudsman says the law is at odds with international human rights commitments and EU asylum rules, the government of Prime Minister Petteri Orpo has said it must be extended to prevent possible future arrivals.

The exceptional emergency law, initially approved for a year in July 2024, was part of the government's response to more than 1,300 migrants from countries such as Syria, Iraq and Yemen entering Finland from Russia in 2023. That phenomenon also prompted Finland to close the border with Russia.

The flow of migrants stopped after Finland closed down all official border crossing points at the end of 2023, and in 2024 only eight people crossed the border illegally after January, interior ministry data showed.

The government needs the support of three quarters of lawmakers in the 200-strong parliament to secure an extension of the law, a high bar reflecting the fundamental principles at stake.

The independent senior official charged with overseeing the legality of government actions said this month that the proposal to extend the asylum ban had insufficient reasoning, emphasising that emergency legislation must only be temporary in nature.

The official, known as the chancellor of justice, also said the threat assessment regarding migrants was insufficient and urged the government to explore alternatives.

The current emergency legislation expires on July 21.

(Reporting by Essi Lehto and Anne Kauranen, editing by Terje Solsvik and Gareth Jones)