OTTAWA, July 14 (Reuters) - Canada's holdings of debt issued by U.S. mortgage finance agencies Fannie Mae (FNM.N: Quote, Profile, Research) and Freddie Mac (FRE.N: Quote, Profile, Research) are well within the limit of 6 percent of its foreign reserves, a Department of Finance official said on Monday.

As of June 30, Canada held US$43.08 billion in its "exchange fund account," which includes foreign currency securities and deposits, gold and special drawing rights but excludes its IMF reserve position.

"The foreign reserves portfolio is actively managed taking into account credit and market factors. Credit exposure to the two U.S. agencies is currently well within portfolio limits established for these entities," the Canadian official said.

Concerns have grown in the past few days that Fannie and Freddie may be in financial difficulties as mortgage defaults rise even among borrowers with solid credit.

On Sunday, the U.S. Treasury Department and Federal Reserve announced a plan to lend money and buy equity if necessary in the enterprises, which own or guarantee US$5 trillion in debt.

Canadian government rules allow the foreign currency reserves to be comprised of up to 3 percent of any individual government-supported entity, or GSE.

The official would not say exactly how much of that debt Ottawa held, citing "commercial sensitivity reasons."

Canada has gradually reduced its holdings of U.S. dollar securities as a percentage of its total reserves, apparently hedging against U.S. financial market woes. Holdings in euros now outweigh those in dollars.

In June, its holdings of U.S. dollar deposits and securities totaled US$19.96 billion and its holdings in euros totaled US$21.41 billion. In June 2007, Canada's U.S. dollar holdings were US$19.49 billion while euros were a smaller US$17.70 billion.

The rest was held in Japanese yen. (Reporting by Louise Egan; Editing by Frank McGurty)