Asian shares fell Friday, tracking overnight weakness in global equities, but the dollar gained as U.S. debt yields rose after several Fed officials expressed concerns about continued bond buying.

Minutes from the Federal Reserve's December policy meeting released Thursday showed some  members of the Federal Open Market Committee were increasingly concerned about the potential risks of the Fed's asset purchases on financial markets, even if it look set to continue an open-ended stimulus program for now, Reuters reported.

The Fed's asset buying policy has been a crucial factor underpinning investor risk appetite and supporting global equities, so the more hawkish Fed minutes unnerved financial markets Thursday, driving U.S. Treasury yields to a near eight-month high and weighing on equities and oil, while bolstering the dollar.

The dollar extended gains early in Asia Friday, hitting its highest since July 2010 against the yen at 87.78, while the euro fell to a three-week low of $1.3022, Reuters reported. The U.S. dollar hit a near four-week high against a basket of major currencies on Thursday.

MSCI's broadest index of Asia-Pacific shares outside Japan fell 0.4 percent, after scaling its highest since August 2011 on Thursday.

Australian shares slipped 0.5 percent, with investors pulling back after a sharp two-day rally which took shares to their highest in more than 19 months on Thursday.

South Korean shares opened down 0.1 percent. Japan's Nikkei opened sharply higher, up 2 percent, to its highest since March 2011 on the back of the tumbling yen. Japanese markets were closed from Monday through Thursday for the New Year's holidays. The Nikkei ended 2012 with the sharpest yearly gain since 2005.

U.S. crude inched down 0.2 percent to $82.78 a barrel.