Apple's legendary co-founder and top ideas man Steve Jobs has resigned as chief executive in a move long expected after he began a dramatic fight with cancer.

In a written statement, Apple, the world's second most valuable company by market capitalization, announced that chief operating officer Tim Cook will replace Jobs as CEO, and said Jobs would become chairman of the board.

Jobs is seen as the heart and soul of Apple, with analysts and investors repeatedly expressing concern over how the Cupertino, California-based company will fare without the figure seen as its driving force.

News of Jobs' resignation helped boost shares in major competitor Samsung while other industry players also benefited with analysts seeing a window of opportunity for rivals of the trailblazing US firm.

The announcement saw Apple shares tumbling over five percent in after-hours US trade.

Shares in Samsung Electronics meanwhile, whose Galaxy tablet is sparring with the iPad, jumped three percent, while LG Electronics surged four percent.

Speaking about Jobs' resignation, Apple board member Art Levinson said in a statement: "Steve's extraordinary vision and leadership saved Apple and guided it to its position as the world's most innovative and valuable technology company,"

Gartner analyst Van Baker saw no reason for investors to panic as the iconic brand lost value in Asia trade.

"My suspicion is that Apple will do just fine," Baker told AFP. "There are so many talented people there and Steve's attention to detail is baked into the culture."

Jobs will still be around as chairman of the Apple board and the company has product plans mapped, according to the analyst. Apple is expected to launch a fifth-generation iPhone in September or October.

"Apple is an execution monster, and that includes products, supply chain and marketing," Baker said. "Their roadmap is in place; I'm sure they are already working on the next iPad."

No reason was given for Job's resignation, but his health problems, including a lengthy medical leave for a liver transplant in 2009 and his gaunt appearances at public events, fueled speculation he would have to give up the everyday running of the company he co-founded in 1976.                       AFP