The pair, who met twice in 2018, have held talks at least annually in the last five years, unsettling Western powers worried over Putin's proximity to an EU and NATO member state leader. Putin last visited Budapest in 2017.

Orban, a self-styled "illiberal" strongman and anti-immigration figurehead for nationalists around Europe and beyond, has adopted a policy of "Eastern opening" in recent years.

He has tasked his foreign ministry with sourcing trade deals in countries such as Russia, Turkey and China, a strategy that has seen the 55-year-old maverick accused of cozying up to autocrats and dictators.

"Orban presents himself as the bridge between the East and the West," said Peter Kreko, director of Budapest-based think tank Political Capital.

"Even if Hungary is a member of the Euro-Atlantic alliance, he opens to the East," he told AFP.

Eastern opening

Last year during a visit to Moscow, Orban denounced EU sanctions on Russia over its annexation of Crimea.

Next week Turkish President Recep Tayyip Erdogan visits Orban in Budapest, soon after praising the Hungarian for his "support" of Ankara's military operation in Syria.

Orban has argued that Hungary's national interest lies in allying with Turkey to avoid it sending millions of Syrian refugees currently in the country toward Europe.

Earlier this month Hungary held up a joint EU statement condemning Turkey's incursion.

Orban held an anti-Russian stance before becoming premier in 2010, but now calls his foreign policy a "pragmatic" courting of regional powers.

Brushing off western criticism as "hypocrisy," he often cites German and French business and political engagements with Moscow.

Putin's regular visits to Orban allows the latter to "demonstrate to his own electorate what an important leader he is," said Andras Racz, a Russia expert with the German Council on Foreign Relations.

"But it is equally symbolic that Putin is the only important leader doing so, no one from the EU or NATO is," he told AFP.

Increasing dependence

Wednesday's agenda, which will feature a joint press conference after their meeting, covers talks on Hungarian-Russian trade and energy relations -- primarily the joint project to expand Hungary's only nuclear plant at Paks, south of Budapest.

In 2014 Orban signed a 10-billion euro ($11 billion) loan deal with Putin to build two reactors at the facility, but the two sides have agreed to renegotiate the loan terms.

With Hungary relying on Russia for around 85 percent of its energy needs, the pair are also due to sign a major gas supply deal.

They will also finalise a joint consortium project to make railway carriages for Egypt and discuss the headquarters move to Budapest of a controversial Russian-led development bank.

Called "Putin's Trojan horse" by critics, the International Investment Bank (IIB)'s shift to an EU capital is seen by some observers, including the US, as potentially enabling spying activity by Russia.

The bank firmly denies the claims, while Budapest says hosting the IIB will help Hungary become an international financial hub.

"All the cooperation points to increasing energy dependence on Russia, while under the surface there are increasing signs that the Hungary-Russia relationship is highly asymmetrical," Kreko said.

The IIB headquarters move, the Egypt train carriages deal, and a separate expensive refurbishment of Budapest metro carriages by a Russian firm are "good for Russia, bad for Hungary," he said.