Monday was the deadline for sending the document and will be followed on Tuesday with a handover of the two sides' printed counter-memorandums in the Hague, Ljubljana and Zagreb.

Hearings at the Hague tribunal are expected to be held in May and June next year and then the tribunal will make a ruling on the basis of the arguments and documents, possibly in the first half of 2015.

The parliamentary Foreign Policy Committee endorsed Slovenia's memorandum last Wednesday behind closed doors after the government confirmed it at the end of October.

The Slovenian memorandum is a well-kept secret on 650 pages with another 5,450 pages attached, of which 250 pages are maps. Foreign Policy Committee chair Janja Klasinc said she believed Slovenia argumented its case very well.

The memorandum was endorsed also by parliament before it was sent to Croatia in February. At the time the MPs adopted a statement saying that the tribunal needed to determine "a territorial junction of Slovenia's territorial waters with the high seas" - a key issue in the dispute.

The centrepiece of the dispute, which is stemming from 1991 when both countries left Yugoslavia, is Slovenia's territorial junction with the high seas. Slovenia claims it has always had access to international waters, which qualifies it as a maritime nation.

Following a series of failed attempts to resolve the dispute bilaterally as well as with the help of the EU, Slovenia and Croatia decided to refer the issue to international arbitration.

Prime ministers Borut Pahor and Jadranka Kosor signed the border arbitration treaty on 4 November 2009 in Stockholm under the auspices of the Swedish EU presidency.

The deal was based on a proposal by the then enlargement commissioner, who helped them reach agreement on the manner in which to resolve the dispute, which in turn enabled Croatia to resume EU membership talks.