Mayor Bill de Blasio and Gov. Andrew Cuomo both skipped Wednesday’s funeral for retired NYPD Detective Luis Alvarez, who spent his dying days fighting for fellow first responders sickened by the Sept. 11 terror attacks.

The notable absences came little more than a month after both officials were no-shows at a solemn, May 30 ceremony to dedicate a Ground Zero memorial to the 2,000-plus victims killed by exposure to toxins during the recovery effort.

While hundreds of mourners showed up to honor Alvarez at Immaculate Conception Church in Astoria — including NYPD Commissioner James O’Neill, US Rep. Alexandria Ocasio-Cortez, US Rep. Carolyn Maloney, US Rep. Peter King and Jon Stewart — de Blasio was visiting Iowa in pursuit of his long-shot presidential bid.

De Blasio, who attended Alvarez’s wake on Tuesday afternoon, tweeted news coverage of the funeral from his mayoral account.

“Luis Alvarez spoke out with the clearest, strongest voice for our brothers and sisters who answered the call during our city’s darkest days,” he wrote.

“It’s up to us to make sure the work of fully funding the 9/11 Victims Compensation Fund is continued.”

Cuomo’s official schedule showed him in Albany, with no public events, on Wednesday, which marks the 53rd birthday of his longtime girlfriend, celebrity chef Sandra Lee.

Cuomo spokesman Don Kaplan said that Alvarez’ funeral “was a private event and we respect that and believe the best way to honor his memory is to keep fighting to ensure the federal government provides Ground Zero survivors with the benefits and support this nation owes them.”

In addition to skipping the funeral, Cuomo didn’t attend Alvarez’ wake, which was held Tuesday afternoon and evening in Oceanside, LI, even though he was at Jones Beach State Park to take the first ride on a new zip line attraction there.

Cuomo tweeted two messages Wednesday morning from his gubernatorial account — about a mural at the new Shirley Chisholm State Park in Brooklyn and President Trump’s abandoned citizenship question on the 2020 census — but didn’t mention Alvarez.

He later tweeted a third time, demanding a probe of Trump’s handling of Hurricane Maria relief efforts on Puerto Rico.