South Ossetia along with Abkhazia, another Georgian breakaway region, are a major source of tension in relations between Georgia and Russia. Georgia accuses Russia of trying to annex the provinces. North Ossetia has close ethnic and historical ties with its southern neighbor.
Taimuraz Mamsurov told foreign envoys at a presentation in the Russian Foreign Ministry: "I am asking you to support the justified intent of the Ossetian people to be united."
South Ossetia, a small territory with a population of less than 100,000, has been seeking international recognition of its de facto independence from Georgia since the breakup of the Soviet Union. However, Tbilisi is only prepared to grant it broad autonomy.
Speaking at a RIA Novosti news conference on Tuesday, Georgian Ambassador to Russia Erosi Kitsmarishvili said the unification of South and North Ossetia's would contravene international law.
"On the subject of unification, there is such a thing as international law, which recognizes the territorial integrity of Georgia and is not subject to revision," the diplomat said.
Ex-Soviet breakaway regions have stepped up their drive for independence since Kosovo's declaration of independence in February. Georgia's Abkhazia and South Ossetia, along with Moldova's Transdnestr, have since asked Russia's parliament, the UN and other organizations to recognize their independence.