WASHINGTON — Several House Republicans expressed concern on Thursday that a merger of Comcast and Time Warner Cable would give the new company undue influence over the potential success of cable channels whose programming might compete with Comcast’s.

At a four-hour hearing of the House antitrust subcommittee, representatives from a few, mostly Republican states raised questions about Comcast’s decision after its takeover of NBCUniversal to drop RFD-TV from its cable service in Colorado and New Mexico. RFD focuses on largely rural interests like agribusiness, Western sports and music, and rural lifestyle issues.

Republican and Democratic representatives also raised concerns about Comcast’s post-merger ability to pick winners and losers in the cable and broadband business because of its influence over regional sports networks, several of which it owns, and over Internet video companies whose offerings compete with Comcast’s television programming.

In the end, however, several members expressed the view that, although Congress has no direct authority over the merger, they expect that not enough documented antitrust problems exist to block the deal.