Apple's latest-generation iPhone is expected to make a rock star entrance on Thursday, drawing crowds that quickly empty shelves at the firm's shops.
"Initial demand for the new iPhone is incredibly robust," Deutsche Bank market analysts Chris Whitmore and Joakim Mahlberg said in a note to investors.
"We anticipate another ‘Apple event’ with long lines, heavy store traffic and stock outs."
Apple set a single-day record for iPhone orders when advanced sales launched last week, receiving 600,000 in 24 hours.
AT&T, the exclusive carrier for the iPhone in the United States, said pre-order sales for the iPhone 4 were "10-times higher than the first day of pre-ordering for the iPhone 3GS last year."
AT&T suspended a troubled early ordering process because of the heavy demand.
Deutsche Bank analysts have raised their projections for iPhone 4 sales, estimating that Apple would sell 44 million this year and 55 million next year.
Standard & Poor's Equity Research Services rated Apple stock a "strong buy" based on the iPhone, iPad, iPod and Macintosh computer maker's hot products.
"Apple has transformed from the hip iPod maker to a leading-edge technology giant with a hand in some of the fastest-growing technology hardware markets," said Equity Research information technology analyst Clyde Montevirgen.
"By competing in the smartphone, laptop, tablet, and retail markets, and outperforming formidable competitors along the way, Apple has effectively expanded its total available market size and renewed its long-term high-growth potential."
The iPhone 4 goes on sale in Britain, France, Germany, Japan and the United States on June 24.
Some people began queuing outside the Apple Store in downtown San Francisco on Monday to be among the first to get their hands on an iPhone 4.
In Japan, Japanese mobile phone carrier Softbank also faced a deluge of pre-orders for the latest iPhone, with queues snaking around outlets and its online store overwhelmed by demand.
Apple chief executive Steve Jobs unveiled the new iPhone earlier this month. It features video chat, can shoot and edit high-definition quality video and has a crisper resolution screen.
The iPhone 4 costs 199 dollars (US) for the 16 gigabyte model and 299 dollars for the 32GB version.
"Right now, Apple is leading the industry," said analyst Rob Enderle of Enderle Group in Silicon Valley. "Every indication is that the iPhone 4 launch will be successful unless AT&T really screws it up. AT&T remains Apple's Achilles heel in this endeavor; the product looks fine."
The smartphone, which comes in black and white versions, will be available in 18 other countries in July and 24 more in August.
Cupertino, California-based Apple has sold more than 50 million iPhones since it launched the device in 2007.
Explore further: Apple to unveil new iPhone operating system