BRUSSELS, Sept 10 (Reuters) - Five candidates have come forward for the post of president of the huge European Investment Bank, Belgian Finance Minister Vincent van Peteghem said on Friday, the first of several top European Union jobs which member governments will haggle over in the next 12 months.

The government-owned EIB calls itself the world's biggest multilateral financial institution by assets and will be a key player in funding Europe's ambitious transition towards a net-zero-carbon and more digitised economy.

EU countries also decide next year who will head the bloc's top three institutions - the Commission, Council and Parliament - plus its foreign policy chief. Choices for one post affect others due to the need to maintain balance on gender, political affiliation, nationality and country size in the appointments.

The EIB's current head, Germany's Werner Hoyer, has held the position since 2012. He will step down at the end of the year, leaving a vacancy at a bank that has a balance sheet total of 544 billion euros ($582.24 billion) and subscribed capital of 249 billion euros.

The front-runners among the five candidates to replace him are Denmark's Margrethe Vestager, a liberal European Commission vice president in charge of the key competition portfolio, and Spain's socialist Finance Minister Nadia Calvino.

Also interested are the politically non-affiliated Italian central banker Daniele Franco, Poland's right-wing former Finance Minister and current EIB Vice President Teresa Czerwinska, and Sweden's socialist former Energy Minister and also current EIB Vice President Thomas Ostros.

"We can say we are really spoilt for choice because all the candidates are excellent," German Finance Minister Christian Lindner told reporters on Thursday.

The EIB is the lending arm of the EU and is active in 160 countries offering loans, guarantees, equity investments and advisory services. It is especially focused on fighting climate change and preserving the environment and sustainable energy.

EU officials say the choice of the new EIB head is linked to the choice on the next head of banking supervision entity, the Single Supervisory Mechanism, which is due to be picked by the European Central Bank on Sept. 13.

Germany's Deputy Central Bank Governor Claudia Buch and her Spanish counterpart Margarita Delgado are both in the running. If the Spaniard gets the SSM job, it would narrow Calvino's chances for the EIB, because two Spaniards in top finance jobs would be seen as too many.

Conversely an appointment of Buch for the SSM, who is seen as a front-runner, would boost Calvino's chances, officials say.

Vestager has the backing of the Renew political group of EU liberal parties, which includes the French ruling party of President Emmanuel Macron, but some French officials have cautioned that the backing of Paris was not assured.

The EIB appointment will be discussed next week at a meeting of EU finance ministers in Spain but a decision is seen likely only in October, officials close to the talks said. ($1 = 0.9343 euros) (Editing by Richard Chang)