Battalion-size battle groups are currently deployed in Lithuania, other Baltic states and Poland. Countries in the region are seeking to convert them into brigades, which would increase the number of troops serving within the units by several times.
A decision is expected at the upcoming NATO summit in Madrid in June.
"We will find out eventually in Madrid. Until then, we need agreement as there's no consensus yet, and we just have some countries that think this is a big burden for NATO," Anusauskas told reporters on Wednesday.
In Lithuania, Germany is leading the international force, with Anusauskas saying that "we see very positive signs" from this country when it comes to the expansion of the force.
Some 1,600 allied troops are now serving within the NATO international battalion stationed in Rukla.
Countries in the region are seeking more NATO allied forces in response to the Russian invasion of Ukraine.