Debate centers not on the amendment to Article 47 of the constitution itself, but on a separate proposal that the change take effect only seven years after Lithuania joins the EU.
Under the already closed EU accession chapter on the free movement of capital, Lithuania pledged to end restrictions on foreign ownership of agricultural land upon entry to the EU.
Requesting a seven-year transition period would mean reopening negotiations on that chapter at a time when Lithuania is rushing to wrap up talks.
Prime Minister Algirdas Brazauskas told Parliament on Jan. 17 that the ruling coalition was divided on the issue of a transition period, but he hoped it would reach consensus before the vote.
The amendments, he said, were "a common concern of all parties" adding that it was essential they be approved.
A draft law accompanying the constitutional amendment, where the clause on a transition period may be inserted, specifies that farmland may only be sold to foreign physical and legal persons that meet Lithuania's "Euro-Atlantic integration criteria" - in other words those based in EU member states or associate countries, member states of the Organization for Economic Cooperation and Development, members of NATO and countries party to Europe's common market agreement.
Lithuanian municipalities and companies, which are currently barred from such holdings, would also be able to own farmland.
To adopt constitutional amendments, Parliament must vote twice, with at least three months between the votes and a two-thirds majority, or 94 votes are required in both instances.
But with the ruling Social Democrat and New Union parties holding 76 of the 141 seats in Parliament, they will need opposition support even if they manage to agree among themselves.
Some opposition MPs have threatened to torpedo the draft constitutional amendment if a transition period is approved.
Ahead of the main votes Parliament on Jan. 15 voted 89 to six with nine abstentions to approve the constitutional amendments on farmland for further consideration but postponed debate on when the changes would take effect.
"I can't understand why an owner's right to sell land freely and at as high a price as possible should be limited," Conservative faction leader Andrius Kubilius told Parliament.
"The constitutional amendments were drafted in a different political context. If the ruling coalition changes its position, we will demand that the project be returned to the constitutional amendment commission and redrafted from scratch," he warned.
If a transition period were requested, Kubilius said he would propose not amending the constitution at all. "In such a case there'd be no need to rush, we'd have five or six years to calmly consider the matter," he said.
But Vytenis Andriukaitis, chairman of the Parliament's European affairs committee, retorted that the need for a transition period was "quite obvious" since the Spanish EU presidency was calling for a five-year transition period before the EU begins providing financial aid to agriculture in new member states.
Andriukaitis proposed Parliament call for a transition period but not specify its length. That would enable Lithuanian negotiators to seek a trade-off with the EU between funding for agriculture and the number of years before foreigners would be able to buy Lithuanian farmland.
Meanwhile, MP Kazimiera Prunskiene said lawmakers had a "moral duty" to heed widespread calls by Lithuanian agricultural workers' associations and landowners for a seven-year transition period on farmland sales to foreigners.