HONG KONG/TAIPEI -- Apple's iPhone suppliers are cutting tens of thousands of seasonal jobs months earlier than normal as the industry suffers one of its most severe downturns in a decade.

Around 50,000 contract workers have been let go since October at Foxconn Technology Group's most important iPhone factory at Zhengzhou, in China's Henan Province, according to an industry source familiar with the situation. Normally, the contracts of these workers would be renewed every month from August until mid- to late January, when the workforce is traditionally scaled back for the slow iPhone production season.

The scale of the cuts is not necessarily deeper than previous years, it is simply significantly earlier, industry sources said. "It's quite different this year to ask assembly line workers to leave before the year-end," a source with knowledge of Foxconn's reductions said.

Other important iPhone suppliers have let workers go much earlier than usual as they struggle with slower-than-expected demand for Apple's iconic product. The California tech giant earlier this month shocked the market by warning of a slump in revenues at the end of 2018. This year is also shaping up to be difficult, with further declines expected in the smartphone market, while the ongoing U.S.-China trade war is taking a heavy toll.

Pegatron, Apple's second-biggest iPhone assembler, began canceling monthly labor contracts in November.

A source close to the company said its normal practice was to reduce the 200,000-strong head count by tens of thousands every month until reaching about 100,000 -- the minimum required for daily operation, according to one source familiar with the situation. "And for [2018], it just happened sooner than in the past because of poor demand."

Industry sources said early cutbacks were happening further down the supply chain as well. One key component supplier based in Shenzhen had asked 4,000 workers to take an extended "vacation" from October to March, a person with knowledge of the situation said. "The company has not actively laid off those workers yet. It will decide whether or not to lay them off after March 1," the source said.

Meanwhile, Foxconn -- formally Hon Hai Precision Industry -- is in the middle of an aggressive cost-cutting program as it braces for a difficult 2019. In addition to letting contract workers go early, it is hoping to reduce expenses with an organizational restructuring, according to people close to the Taiwanese company. It has recently merged business units making Apple's MacBooks and iPads with another division making laptops and desktops for Dell and Acer.

The result of the consolidation will be steep cuts to management jobs and back office support staff such as human resources, administration, accounting and finance, and utility support jobs. "Previously, each business unit had its own supporting staff, and by merging business divisions, Foxconn can slash some 50% of those supporting jobs and even condense managerial positions too," a person familiar with the reshuffle told the Nikkei Asian Review.

The reorganization is part of Foxconn's push to cut 100,000 jobs out of about 1.1 million by the end of 2018 across all of its affiliates and subsidiaries, as reported by Nikkei Asian Review in November. Foxconn aims to cut costs by some 20 billion yuan ($2.96 billion) in 2019 compared with 2018, according to an internal document dubbed the "1031 project" seen by Nikkei.

Foxconn counts Apple as its top customer but the company also supplies to HP, Dell, Amazon.com, Huawei Technologies, Xiaomi, and many other global tech brands.

The number of contractors it uses can vary significantly year to year due to demand and the adoption of automation in factories, industry sources said. It is unclear what percentage of contractors has been let go early from Foxconn's Zhengzhou factory, which has seen peak employment fall from 400,000 to 300,000 in recent years due to the introduction of automation and efficiency enhancements.

Both Foxconn and Pegatron recently revealed sharp declines in monthly revenues as the smartphone slowdown accelerates. Foxconn suffered a more than 8% decline in December over the same month in 2017. Pegatron said December revenue had plunged nearly 40% from November -- the second straight month of decline -- due to slow demand for consumer electronics.

Foxconn and Apple did not immediately respond to Nikkei's request for comment. Pegatron declined to comment.