Although Finns should be able to travel to Estonia without passports in the autumn of 2007, Finland's Minister of the Interior Kari Rajamäki (SDP) says that the matter is far from certain.
Estonia and the other new member states of the European Union are scheduled to join Schengen next year, but Rajamäki said in an interview published in Monday's edition of the Social Democratic Party newspaper Uutispäivä Demari that the matter is not a "done deal".
Currently 15 countries, including Finland, are parties to the Schengen treaty, whose purpose is to ease free travel between signatories. There are no routine border checks within the Schengen zone.
Rajamäki told Helsingin Sanomat on Monday that he did not want to single out Estonia - he was merely discussing possible factors that might slow down the implementation of the treaty in general.
One possible obstacle involves the new member countries themselves.
Assessments of the readiness of the new EU members to join Schengen are currently been made, and the process is to continue in the autumn.
"The Baltic countries are not at the tail end", Rajamäki said on Monday.
The readiness of the countries to join Schengen will be .....
.... decided by the Council of ministers on the basis of assessment reports in December this year. The meeting will be chaired by the Minister of the Interior of Finland - in all likelihood, Rajamäki himself.
The meeting will decide if the present Schengen countries have confidence in the border security of the aspiring new members. Confidence in the integrity of border controls is important, because the Schengen countries effectively outsource their own border inspections to each other.
Another potential impediment would be a possible delay in the implementation of new information-sharing technology being set up for Schengen, which should be ready and tested for use before the zone can expand.
A new information system is needed, because the present one, which dates back to the early 1990s, would not be able to accommodate ten new members. The system should be ready in March next year if it is to be operational the following October.
"The timetables are a challenge", Rajamäki said on Monday.