By Margit Feher

BUDAPEST--Hungarian oil and gas company MOL Nyrt. (MOL.BU) said Tuesday that it has filed a request for arbitration with an international arbitration institution to settle a dispute over its Croatian unit and peer INA d.d. (INA.ZG) with the Croatian firm's fellow owner, the Croatian government.

MOL filed the request with the International Center for Settlement of Investment Disputes to commence arbitration proceedings under the Energy Charter Treaty against Croatia for "breaching certain of its obligations and undertakings in relation to MOL's investments in Croatia," MOL said in a filing with the Budapest Stock Exchange without providing details.

The Energy Charter Treaty aims to promote and protect foreign investment in member countries. It grants foreign investors in the energy sector the right to sue the host country in the case of an alleged breach of an obligation of the host state relating to investment promotion and protection.

MOL is one of the largest foreign investors in the Croatian economy.

"MOL has certain legal obligations vis-à-vis its shareholders and stakeholders to pursue good-faith negotiations. However, it is also under legal obligations to commence legal action to enforce its rights," MOL said. The company wasn't immediately available for further comment.

Under a privatization agreement, Croatia should have taken over INA's loss-making natural-gas business in 2009, but the government in power then asked for a two-year delay. To date, the takeover hasn't happened.

The Hungarian energy utility, in the meantime, has fulfilled its obligations toward INA under its management agreement and invested nearly 3 billion euros ($4.06 billion) in INA over the past few years, MOL claimed.

Tuesday's arbitration request is the latest development in the Hungarian firm's several-month-long legal and diplomatic dispute with Croatia over the management rights of INA, which currently belong to MOL.

The Croatian government wants to regain control over INA, in which it holds a 44.8% stake following its privatization in 2003. MOL owns a controlling 49.1% and the firm's management rights.

Talks earlier this month between INA and representatives of the Croatian government over the management rights ended without agreement. MOL, in which the Hungarian government is the single largest shareholder with a 24.6% stake, said at the time that it is convinced INA's management model is in line with international practice as well as with Croatian and European regulations.

MOL also said earlier this month that its board had given the green light for preparations to sell its INA holding. The Croatian government, which is under pressure from the European Union to keep its bulging budget deficit in check, likely couldn't afford the deal.

MOL said Tuesday that it remains open to further explore a negotiated resolution to the dispute.

The spat comes amid an ensuing legal battle between the two parties. Croatia issued an Interpol and an European arrest warrant for MOL Chairman and Chief Executive Zsolt Hernadi in October, related to a bribery case in which former Croatian Prime Minister Ivo Sanader was convicted in 2012.

MOL has denied all the Croatian allegations. A Budapest court has declined the extradition of Mr. Hernadi on the grounds that a Hungarian criminal investigation has found Mr. Hernadi innocent.

Write to Margit Feher at margit.feher@wsj.com