It began as a pinch on the massive port of New Orleans, but the widest general strike by longshoremen here has turned into a hammerlock on the city's economy, and port and city officials fear the strike could leave lasting wounds.

In other ports along the East Coast and the Gulf of Mexico, the International Longshoremen's Association (ILA) is conducting a selective strike against container ships in a move to get more money from shipping companies for longshoremen who may have lost work because of automation.

But in New Orleans, longshoremen stopped handling all cargo because they are dissatisfied with local and national union officials. The shutdown has halted all activities along the more than 50 miles of wharves of the country's second largest port, and trade officials estimate the walkout is costing the city more than $2 million a day in lost revenue.

In addition to money lost from cargo sent to other ports, this figure includes money from jobs related to the port, which is New Orleans' chief economic assrt.

"It's intolerable to have this port shut down while other ports continue to operate," says Mayor Moon Landrieu. "A lot of traffic will be diverted, and it will be lost forever."

Grain farmers and a group of almost 100 congressmen today asked President Carter to invoke Taft-Hartley provisions and order New Orleans dock workers back to work for an 80-day cooling-off period. But White House deputy press secretary Rex Granum said the administration did not believe the Gulf port situation "at the present time" warrants it, although the Labor Department is monitoring the strike. Labor Department sources have said any injunction - although unlikely now - is more likely to be targeted against the New Orleans strike than applied to ports where only container operations are shut down.

For businesses here, resumption of normal port activity can't come too soon.

"Two-thirds of the economy of this area is related to the waterfront," said associate port director Henry G. Joffray, "so if you shut two-thirds of it off, the dollars just aren't coming in."

Most of those dollars come from grain. Sixty per cent of the United States' grain traffic ordinarily moves through the port of New Orleans, and two 125-car grain trains used to come through here daily. They were worth about $1,000 per car to Illinois Central Gulf Railroad.

That amounts to "a couple of hundred thousand dollars a day, and that's a lot, even for a big railroad," said John Lager, the railroad's division superintendent, who said he does not know if the grain is being held up or diverted to other ports.

On the docks alone, he said, the railroad has lost $20,000 a day, and it has had to lay off nine train crew members and five clerks.

If the strike continues beyond next week, a spokesman for Baggett Transportation Co., a trucking firm, predicts the company will have to lay off as many as 10 people - one-fourth of its work force.

"Our business has dropped three-quarters," a Baggett representative said this week. "What we get from the few manufacturers in town isn't enough to keep us going. Usually, we have 25 trailers a day coming in. Today, we had nine."

On the water, Hellenic Lines provides an example of the strike's crippling effects. The firm has 2,000 tons of cargo waiting to be loaded - an amount that would bring in $12 a ton, plus $4,000 in port changes. Instead, the cargo sits, while other Hellenic shipments are being sent to other ports.

The strike "is about to close us down," said a spokesman for Neptune Supplies, a firm that stocks the ships in the port. "Our daily sales are off by 85 per cent. If the strike lasts awhile, we're going to have to lay off people."

The selective strike began nationwide Oct. 1 and the wildcat general strike here came four days later. In anticipation of the strike, some inporting firms laid up supplies - stee, liquor and coffee - but spokesmen for some of these companies worry that inventories may run out before the strike ends. Representatives of other firms that costs of some items may have to be boosted to pay for hauling them to other ports.

Along the East Coast, ports are more highly automated than New Orleans, and the issue is containerization, which, ILA president Thomas W. (Teddy) Gleason and the union board contend, costs union members their jobs.

Northeastern shipping executives are trying to talk their Southern counterparts into paying more into ILA pension, benefit and guaranteed income programs. Such firms already pay a loyalty fee to the union for each ton of cargo lost to union members through automation. But, here, only about 25 per cent of the operations are automated, compared with 60 per cent in New York, the nation's biggest port.

Here, some longshoremen feel they call reach a separate agreement with Southern shipping firms, which have balked at aiding Northern companies.

Union members were told that these negotiations "are not an official action by the local ILA but are sanctioned by it."

In addition to their grievances against automated shipping, longshoremen here have complained about their local union leadership. Those bad feelings came to a boil Oct. 4 when, they claim, a union vote to support the national selective strike was "railroaded" past them by local union officials.

Talks between representatives of the strikers and the New Oreans Steamship Association recessed while longshoremen visited other ports to try to gain support for the total strike.

There is no indication of when an acceptiable settlement will be reached or whether the longshoremen will approve it and return to work. There is also no indication of whether New Orleans will be able to recover the business it has lost to other ports.

"The rest of the world doesn't care whether New Orleans works or not," said Peter Low, Hellenic Lines' East Gulf manager. "We're cutting off our nose to spite our face."

"We're going to lose no matter what the settlement is," said Lawrence Williams, an ILA member who is a crew foreman on the docks. "This is going to turn New Orleans into a ghost town."