The Polish President, Alexander Kwasniewski, has told defence leaders Poland must double its spending on military modernisation over the next five years to stand a chance of fitting in with Nato structures.
Vaclav Havel, his Czech counterpart, also warned his countrymen that they will have to dig deeper into their pockets in order to carry their weight in the Western alliance.
The calls for more spending came just over a week after US President Bill Clinton delighted Central European leaders by saying the first wave of Nato expansion to the East should be completed by 1999. They also followed US expressions of concern that for a country anxious to join the alliance, the Czech Republic was not spending enough on defence.
"At last we have a clear timetable for Nato membership," said Pawel Dobrowolski, the Polish foreign ministry spokesman. "It was what we had been wanting to hear for a very long time but the implementation will not be easy."
According to President Kwasniewski, Poland's budget allocation on military modernisation this year of 8bn zlotys (pounds 2bn) will have to be doubled by 2002 in order to make the country's forces fully Nato-compatible.
President Havel did not specify a figure, but his call for greater defence spending followed his government's announcement that it planned a slight reduction in real terms in next year's defence budget.
Although Nato officials have yet to calculate the exact cost of expanding east, studies undertaken by organisations such as the Rand Corporation, a US think-tank, suggest it will be between pounds 30bn and pounds 80bn.
High levels of military expenditure in countries undergoing tough economic transition are not popular. In the Czech Republic opinion is divided on the merits of joining Nato, while in Hungary many support the idea of neutrality.