As Los Angeles struggles to restore its namesake river, a considerable obstacle has arisen -- NBC Universal, which is trying to block a public bike path from traversing its property along the waterway.

The flap over the long-planned path comes as the company is touting the green credentials of a massive residential development proposed for its back lot. So, while the studio paints itself as a friend of the environment -- its real estate project will have hiking trails -- others see moguls trying to keep the public at bay.

One bike advocate said Universal executives told him they feared that people would use the path to lob unsolicited screenplays onto the studio’s nearby production lot -- something that apparently happens at other spots when a Universal film scores big at the box office.

“I think they need to build a higher fence if they’re that worried about it,” said Kent Strumpell, a member of the city of Los Angeles’ bicycle advisory committee.

But the dispute may be only a harbinger of Hollywood clashes to come as bike path promoters push farther upriver. The CBS Studio Center in Studio City sits on both sides of the waterway, and a spokesperson there declined to say if a bike path would be allowed. City officials said Tuesday that they are trying to work with the studio.

Public plans have long called for a bike path to extend north and west from downtown Los Angeles to Canoga Park as a centerpiece of the city’s efforts to revive the long-moribund river. Bike paths along scenic waterways have become a staple attraction of many cities, including Boston, Chicago, Denver, Portland and Sacramento. In fact, there is a bike path along the Los Angeles River from Vernon to Long Beach.

Universal executives said Tuesday that they are not opposed to a bike path on their property -- they just don’t want it to run along the river.

Tom Smith, senior vice president of West Coast real estate for NBC Universal, said a riverside service road where the path would be is, for one thing, very narrow. It is also important for studio operations and traffic.

A bike path is already penciled into Universal’s development plan, Smith said. The company just wants it to loop south, away from the river, deeper into the complex -- and around riverfront production offices that include those for director Steven Spielberg.

“We have some very important, high-profile production companies that are located along that road as well, and security is a concern,” Smith said, adding that NBC Universal plans to create a river gateway park on the northeast edge of the property.

At the same time, the media and entertainment giant is trying to gather public and political support to build 2,937 residential units on the Universal Studios back lot. The company also wants to be a major tenant in a project next to the Red Line subway stop on nearby Lankershim Boulevard. That proposal includes a television production facility, an office tower of up to 24 stories and another building that could be up to 34 stories.

The two projects are still in the planning stages, and the Universal Studios development needs both city and county approvals. Mayor Antonio Villaraigosa has already pledged his support for the projects, although other area politicians have expressed concern over their size.

In the meantime, politicians are growing impatient with Universal’s stance on the bike lanes. “In my conversations with them, they say it’s not practical, but I don’t think they understand it’s one of my personal priorities,” said Councilman Tom LaBonge.

The city has already built five miles of the bike path from Riverside Drive in northern Griffith Park to Fletcher Drive near Silver Lake.

Although the river was lined with concrete decades ago to protect against flooding, narrow strips of land along both sides have been preserved as rights-of-way for maintenance workers. City officials hope to use those strips to build a bike path on one side of the river and a pedestrian walkway on the other.

Jennifer Klausner, executive director of the Los Angeles County Bicycle Coalition, said the bike path potentially offers the chance to give cyclists a way to get across the city without dealing with streets.

“The beauty of the river path is that it’s basically flat and separated from the road for people who want a quieter ride and don’t want to hump it over a hill,” she said.

Los Angeles County Supervisor Zev Yaroslavsky said he wants Universal to study the bike path as part of its environmental reports on its project.

“The fact is that we have a public bike path along some of the most expensive and reclusive properties along the ocean -- from Will Rogers [beach] to Torrance,” he said. “I don’t think it’s a mutually exclusive proposition to have a bike path and a secure studio in the same location.”

steve.hymon@latimes.com

andrew.blankstein @latimes.com