WASHINGTON — Rep. Charles Rangel failed to report as much as $1.3 million in outside income — including up to $1 million for a Harlem building sale — on financial-disclosure forms he filed between 2002 and 2006, according to newly amended records.

The documents also show the embattled chairman of the Ways and Means Committee — who is being probed by the House Ethics Committee — failed to reveal a staggering $3 million in various business transactions over the same period.

This week, Rangel filed drastically revised financial-disclosure forms reflecting new, higher amounts of outside income and numerous additional business deals that had not been reported when the reports were originally filed.

In 2004, for instance, Rangel reported earning between $4,000 and $10,000 in outside earnings on top of his $158,100 congressional salary.

But the amended filings show that after the sale of a property on West 132nd Street, his outside income that year was somewhere between $118,000 and $1.04 million.

The forms filed by House members provide for a range of value on such transactions, so the precise number isn’t publicly known.

Rangel also lowballed his income by as much as $70,000 in 2002, $46,000 in 2003 and $117,000 in 2006, records show.

Only in 2005 did Rangel reveal his total outside income.

Members of Congress are required to disclose all their assets and outside income in an effort to expose possible undue influences.

Rangel’s office insists the Harlem Democrat did not conceal any outside income from the IRS and is paid up on his taxes.

The Post revealed yesterday that Rangel is in arrears on New Jersey property taxes — for property that for more than 15 years he failed to disclose to Congress and the public.

Another area of wide discrepancy in his financial-disclosure forms is where he’s required to list financial transactions.

Every year between 2002 and 2007, Rangel failed to include all his deals for the year, according to records.

On his 2002 and 2003 financial-disclosure statements, Rangel did not include any transactions whatsoever, according to papers on file with the House clerk.

But the amended records filed this month show as much as $310,000 in business deals in 2002 and up to $80,000 in transactions in 2003.

In 2004, Rangel left off his disclosure form as much as $430,000 in stock transactions, amended records show. One of those deals he did include as a transaction on his original disclosure was the sale of the brownstone on West 132nd Street.

But in the same report, Rangel failed to include proceeds from that sale as outside income. That has been revised in the amended report.

Despite the reported sale, city records still show Rangel is the owner of that property.

His nephew, Ralph, who appears to live in the building, wouldn’t answer questions yesterday. Rangel’s office declined numerous requests yesterday for explanation.

The problems with Rangel’s 2004 disclosure report were so glaring that apparently they caught someone’s attention, forcing Rangel to write a letter correcting his failure to fully disclose transactions that year.

“I listed only the real-estate transactions in which we were involved in calendar year 2004 on the transactions schedule because I was not aware of such details as the date and magnitude of the transactions involving our securities holding in the Merrill Lynch account,” he wrote in a May 2006 letter to House Clerk Karen Haas.

churt@nypost.com