An influential group of corporate travel managers has asked the US Transportation Department to reopen its decision-making process for new services to China now that United and Continental are in preliminary merger talks, a group spokesman said.

A decision is expected soon by the department on the competition between American Airlines, Continental Airlines, Northwest Airlines and United Airlines for the new single route.

Each carrier has proposed a different US departure city with service scheduled to begin in March.

The US-China market is lucrative and even more important now because of the industry's financial problems.

The Business Travel Coalition, which represents travel managers of large corporations, asked Transportation Secretary Mary Peters on Wednesday to re-evaluate the China proposals.

Coalition spokesman Kevin Mitchell said a combined United-Continental would dominate new and existing China service to and from the United States.

"The department should not be rushed in a decision with such strategic, long-term implications for travelers, communities and the competitive structure of this important market," Mitchell said.

A spokesman for Peters said the department would not comment on calls to revise its review.

Experts said any deal for United and Continental is still far from certain, and would likely face close regulatory and congressional scrutiny if formally proposed.

Separately, United, Continental and Northwest have asked transportation officials to disqualify American from consideration because of its decision last week to amend its application to add Chicago as a connecting point on proposed flights from Dallas to Beijing.

American made the change because of contractual problems with its pilots union. US-bound flights would still be non-stop to Dallas.

Some aviation experts believe American has taken itself out of the running by adding more time to its China-bound service. But American said in a letter to transportation officials in response to its rivals that its application remains valid and it still hopes to work out non-stop service in both directions, if it wins the award.