WASHINGTON (Reuters) - M&T Bank Corp (>> M&T Bank Corporation) will put a comprehensive plan in place to fix problems with its anti-money laundering policies that had caused regulators to put a hold on its $3.7 billion bid to buy Hudson City Bancorp.

Buffalo, New York-based M&T Bank will submit a plan to the Federal Reserve to improve its monitoring and reporting of suspicious activity, the regulator said.

The bank will also hire an independent consultant to review transactions on any high-risk customer accounts during the period of July 1, 2012 to December 31, 2012, the Fed said.

M&T Bank said in April that regulatory concerns over such procedures were holding up its proposed purchase of Hudson City (>> Hudson City Bancorp, Inc.), which is based in New Jersey.

The deal was initially announced in August 2012 and was worth $7.22 for each Hudson City share.

M&T Bank, which has Warren Buffett's Berkshire Hathaway Inc (>> Berkshire Hathaway Inc.) as a major shareholder, planned for the acquisition to fill gaps in its coverage area on the U.S. East Coast.

Hudson City, which specializes in mortgage lending, has branches in New Jersey and the New York City metropolitan area. The combined network would have 870 branches from Connecticut to Virginia.

The plan hit a snag when regulators raised concerns about M&T Bank's anti-money laundering programs. The bank said in April it hired an outside consultant to help address the concerns.

(Reporting by Douwe Miedema; Editing by Jeffrey Benkoe)

By Douwe Miedema and Emily Stephenson