KINGSTON, Jamaica (AP) _ Hundreds of women sit hunched over sewing machines, stitching up the seams of boys' pants and adding belt loops and buttons to trousers that will be sold in some of the biggest U.S. stores.

They are part of the growing garment-making business in Jamaica.

The women are employed by Noel of Jamaica, one of two Jamaican factories operated by Noel Industries, a U.S. company with headquarters in New York and Ruleville, Miss. The first began operations in 1982.

Hundreds of U.S. garment makers have moved to the Caribbean in recent years to take advantage of the region's low wages and to compete with Asian firms.

Apparel was excluded from the duty-free status granted many other products from the region under the U.S. Caribbean Basin Initiative. But items with U.S. components get special tariff treatment.

To qualify, the U.S. manufacturers send cut material to Caribbean nations where workers sew and finish the garments for shipment back to the United States.

''To stay in business, we had to come to Jamaica,'' said Doug Burkett, general manager of Jamtex.

''We don't make a great profit off of the business here,'' he said. ''But we can stay in business and compete.''

U.S. imports of textiles and apparel from the Caribbean climbed from $315 million in 1981 to $649 million in 1985, according to the U.S. International Trade Commission.

Noel factories make pants for sales in K-Mart, Montgomery Ward, Sears, Roebuck and other stores.

Burkett said the average pay for the 650 workers at Noel of Jamaica is the equivalent of about $20 a week. The national mininum wage is about 27 cents an hour, compared with the U.S. minimum of $3.35 an hour.

Jamaica's National Investment Promotion agency last year estimated production costs for men's polyester slacks, if made here, at $26.62 a dozen, compared with $63.53 in the United States.

End Adv Tues AMs Dec. 30