Amazon.com Inc has forecast a jump in holiday sales — and costs related to Covid-19 — as consumers continued to shop more online during the pandemic.

A company executive added that heightened spending on delivery infrastructure would likely continue over years, and shares fell 2 per cent in after-hours trading.

Since the start of the virus outbreak in the United States eight months ago, consumers have turned increasingly to Amazon for delivery of groceries, home goods and medical supplies, Reuters reported.

Brick-and-mortar shops closed their doors; Amazon by contrast moved to recruit over 400,000 workers and earned $6.3 billion in the just-ended quarter, its second consecutive record profit.