Slovenia is hoping to secure investment from Magna that would create 400 jobs and be the first phase of a potential 1.24 billion euro ($1.48 billion) programme to create a total of about 6,000 jobs over the coming years.

Pocivalsek said the August approval of the investment by the Slovenian Environment Agency came into force on Tuesday after no appeals were filed.

Slovenia is rushing to enable the investment, one of the largest in the country so far, because Magna has said it might build a paint factory in Hungary if Slovenia does not give it the necessary approvals soon.

Magna was not available for an immediate comment.

Another major investment project by the centre-left government will be tested in a referendum next week when voters will decided whether to annul the law that would enable the government to start construction of its flagship 1 billion euro rail link project.

Analysts believe the successful start of the two projects could improve the falling ratings of the centre-left Party of Modern Centre of Prime Minister Miro Cerar ahead of a general election due in June or July next year.