"Finland must apply for NATO membership without delay. We hope that the national steps still needed to make this decision will be taken rapidly within the next few days," the two leaders said in a joint statement, arguing that NATO membership would strengthen Finland's security.
Foreign and security policies in Finland are jointly managed by the president and the cabinet, according to the Finnish constitution. A formal decision would have to be made by the president and the cabinet ministerial committee for foreign and security policy in a joint meeting.
Meanwhile, Speaker of the House Matti Vanhanen said on national radio Yle on Thursday that the president and the cabinet are expected to "make their decisions" this coming Sunday.
Finland is expected to submit an application soon, possibly in collaboration with neighboring Sweden, according to local media reports.
Sweden's parliament will debate the security situation on Monday and Prime Minister Magdalena Andersson will then call a special cabinet meeting where the formal decision to apply will be taken, Expressen newspaper said, citing unnamed sources.
Finland is Sweden's closest military ally and the only other Nordic country not to be a member of NATO.
Finnish public support for NATO membership began to rise in February. Various polls show that it has risen from around 20 percent to more than 70 percent. According to local analysts, 10-15 MPs are expected to oppose the application and membership.