NEW YORK (CNN/Money) - A telecommunications industry group asked a U.S. appeals court Friday to block a new rule that will allow customers to transfer their phone numbers between different providers, saying the rule is "deliberately skewed to favor wireless carriers."

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The United States Telecom Association said it asked the U.S. Court of Appeals in the District of Columbia to delay the order that will allow users to transfer numbers to other wireless carriers and from land lines to cellular phones.

The group's contention is that it is technically harder to move a number from a wireless phone to a land-line phone and this difficulty could cut into business for traditional telecom providers.

"In the past, the [Federal Communications Commission] repeatedly has expressed its commitment to portability rules that are efficient and fair, so they are not a source of competitive advantage for one platform or another," Walter McCormick, president and CEO of the USTA, said in a statement Friday.

"By rushing out a one-sided rule that encourages only land line to wireless transfers, that promise was broken."

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The USTA asked the FCC Thursday to delay the move, but that request was denied.

The FCC said its number portability rules were designed to be a two-way street between land line and wireless carriers and was already in the process of trying to further facilitate difficult transfers.

"We see no reason, based on the instant petition, to delay these benefits to consumers, carriers and to the competitive marketplace," the agency said.