THE 2012 Nobel Prize season opens with the pick for the medicine award, marking the start of a week of announcements and speculation over who will collect the literature and peace prizes.

The medicine prize will be announced in Stockholm at 11:30am (2030 AEDT) at the earliest.

With the awards committees keeping mum on their choices, Nobel watchers are left to play a guessing game.

Swedish media have suggested the medicine prize could go to Japan's Shinya Yamanaka and Britain's John Gurdon for their research in nuclear reprogramming, a process that instructs adult cells to form early stem cells which can then be used to form any tissue type.

James Till of Canada could also be honoured for his related work on blood stem cells.

Other medicine fields cited as worthy of Nobel recognition this year are epigenetics, which studies how genes respond to their environment, and optogenetics, where researchers can turn on or off a nerve cell, for example in a fruit fly or a mouse, to reprogram the brain.

The winner of the Nobel Peace Prize, perhaps the most watched of the prestigious awards, will be revealed Friday in Oslo, and the five-member Norwegian Nobel committee has 231 nominees to choose from this year.

No clear frontrunner has emerged so far, though Coptic Christian Maggie Gobran of Egypt, dubbed the "Mother Teresa" of Cairo's slums, tops the list of one betting site with odds of 6.5-to-1.

The committee keeps the list of nominees a well-guarded secret, but those who are entitled to nominate candidates can disclose the names they have put forward so the list is known to include former US president Bill Clinton, ex-German chancellor Helmut Kohl, the EU and WikiLeaks suspect Bradley Manning.

The head of the Peace Research Institute of Oslo, Kristian Berg Harpviken, follows the work of the committee and each year publishes his own shortlist of possible winners.

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Medicine prize kicks off Nobel prizes