Manhattan US Attorney Preet Bharara’s latest anti-corruption mission has him digging into the United Nations, specifically the office of the president of the UN General Assembly.

There’s plenty to find.

The presidency is a one-year gig, rotated among UN countries on a regional basis. Formally, the presidency carries little real power, but as Bharara’s allegations this week demonstrate, it offers plenty of opportunity for mischief.

Last week a small group of top UN officials and diplomats gathered to celebrate the end of Turtle Bay’s annual gabfest with some finger food, cocktails and small talk. After Secretary-General

Ban Ki-moon made some jokes, the current president, Denmark’s Mogen Lykketoft, turned serious.

With raging poverty and wars all around, he said, we need to get back to work “now, tomorrow.”

Lykketoft’s short, humorless world-saving sermon was remarkable, as the entire room was abuzz about the much more mundane business of how one of his predecessors was forced to perform a perp walk downtown several hours earlier: John Ashe of Antigua and Barbuda was arrested by the feds on charges of bribery-related tax evasion.

According to the rap sheet, Ashe, who was General Assembly president two years ago, allegedly received millions of dollars from a Chinese-based real-estate mogul, Ng Lang Seng.

Ng allegedly used several UN-related NGOs to transfer cash, gifts and airfare tickets to Ashe and his co-defendants, trying to enlist their help in promoting a pet project: He wanted to build a UN center in Macau.

UN officials and sympathizers immediately rejected any connection between them and Ashe, offering the weak spin that the office of General Assembly president is nothing but a “ceremonial” post with no real standing in the institution.

It would be nice if that were true, considering the rogues gallery of GA presidents. There was the defrocked Catholic priest, Miguel d’Escoto, who tried to use the presidency to convert the General Assembly into an anti-imperialist funhouse, informed by the likes of Noam Chomsky. Oh, and d’Escoto had previously served as foreign minister under Nicaragua’s Sandinista chief Daniel Ortega.

Others used the office to promote their own countries’ not-so-pure interests, like Serbia’s Vuk Jeremiććc, who in 2012 tried to whitewash his nation’s role in the Balkan wars a decade earlier.

Or Qatar’s Nassir Abdulaziz Al-Nas-ser, who got the position in 2011, shortly after the corrupt soccer-ruling body, FIFA, awarded Qatar the right to host the 2022 World Cup.

But how about GA presidents from regimes so notorious that even your most enlightened loon would shun them? There was Ali Abdussalam Treki, Libyan foreign minister under Moammar Khadafy, who successfully presided over the General Assembly in 2009.

And last year, as the UNGA passed its usual vacuous resolutions promising equality for all, its president was Sam Kutesa — who was also serving as foreign minister of Uganda, where new laws had just declared homosexuality a felony.

And when Kutesa, who has business interests in Africa that include arms-sales, hired his son as a UN “adviser,” no one raised an eyebrow. This is the office of the GA president, I was told at the time. UN employees work there, but it’s mostly financed by the president’s country, so good governance rules like frowning on nepotism don’t apply.

No wonder the Chinese businessman allegedly had his eye on this gallery of clueless gasbags and shady characters. Their dealings with UN affiliates and related NGOs is a target-rich environment for anyone seeking undue influence over a world body handling huge sums of money and wielding influence at key corners of the world.

Even better: It’s based right here in New York, the financial center of the world.

So Bharara last week vowed to examine whether “corruption is business as usual at the United Nations.” Good. Start with the office of the General Assembly president, but don’t stop there. We need to know how high the reach of Chinese players, and perhaps other nefarious operators, got.