The 2.5 million-member AFL-CIO is poised to announce its early support of Democratic state Comptroller Tom DiNapoli almost two full weeks before its scheduled endorsement convention in Albany on Aug. 15-16.

The endorsement will come at an 11 a.m. press conference outside the AFL’s HQ at 100 Swan Street tomorrow that will be attended by the federation’s president, Denis Hughes, along with various and sundry labor leaders.

This doesn’t come as any big surprise, since DiNapoli has been slowly rolling out the official endorsements of many AFL members. His support is particularly strong among the public employee unions, which is interesting, considering their rather cool relationship with the party’s standard-bearer, AG Andrew Cuomo.

As I wrote in my DN column this morning, the teachers and the public employee unions aren’t sold on Cuomo – largely due to proposals that are unpopular with the leadership like spending and property tax caps, wage freezes and support for charter schools.

If they choose to actively oppose the AG, then it would be nearly impossible for Cuomo to land the two-thirds weighted vote to get the AFL-CIO nod. But that’s a very big if. A more likely scenario is that they remain neutral, which means Cuomo merely needs to get two thirds of the members who are actually voting – minus those abstaining.

That’s a much easier lift, and one Cuomo could achieve if he gets all of the private sector unions (the AFL split is about 50-50, public-private). He’s already well on his way with early nods from: The New York State Building Trades Council, the Retail, Wholesale and Department Store Workers Union, UFCW Local 1500 (I forgot these guys in the column, so sorry) and District 15 of the International Association of Machinists and Aerospace Workers.

Today, Cuomo added one more: The New York State Pipe Trades Association.

The Cuomo campaign is very sensitive to possibly being labled “anti-union”, and so is making a clear distinction between private unions that, as one source explained to me, “represent real working people”, and public sector unions whose expensive contracts and pensions and refusals to agree to give-backs has labled them special interest No. 1 in many minds.

NYSUT in particular has made it clear it is open to possible remaining neutral in the race. In 1994, when then-Sen. George Pataki ousted Democratic incumbent Gov. Mario Cuomo, NYSUT endorsed Cuomo. (This is fixed).

The last time the AFL-CIO was neutral was in 1998 when then-Gov. George Pataki was challenged by Democratic then-NYC Council President Peter Vallone.

NYSUT will be meeting in advance of the AFL-CIO convention – Aug. 9, 10 and 11 – in Albany to decide which way it wants to go in the race.

One thing is clear: The AFL-CIO is taking a new approach to legislative endorsements, particularly when it comes to the Senate. It will no longer ally itself with one party or the other, preferring to take a case-by-case approach.

Labor sources have told me to expect fewer-than-normal endorsements in the Senate, which stands to reason, since the AFL has already started targeting key incumbents it deemed anti-working men and woman.