"Her Majesty's Government today announces its intention to proceed with an initial public offering of Royal Mail," said a joint statement, which added that the IPO was "expected to take place in the coming weeks".
Royal Mail is to list on the London Stock Exchange, while the coalition government said it would "retain flexibility around the size of the stake to be sold".
The government had in July announced plans to privatise more than 50 percent of Royal Mail following a major restructuring of the organisation in recent years, triggered by fierce competition from email.
Media reports say the part sale of Royal Mail could be worth up to 3.0 billion ponds (USD 4.74 billion).
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The government previously said that it would take on Royal Mail's historic pension deficit.
"This is an important day for the Royal Mail, its employees and its customers," Business Secretary Vince Cable said in Thursday's statement.
"HM Government is taking action to secure a healthy future for the company. These measures will help ensure the long term sustainability of the six days a week, one-price-goes-anywhere universal postal service.
Cable, a member of the Liberal Democrats which share power with Prime Minister David Cameron's Conservatives, confirmed Thursday that 10 percent of Royal Mail shares would be handed out to its employees free of charge.
Around 150,000 staff will be eligible to get a free stake in the business under Britain's largest employee share scheme of any major British privatisation for almost 30 years.
The government has argued that partial privatisation will allow Royal Mail the freedom to raise capital, continue modernising and meet booming demand for online shopping delivery.
The coalition government relaunched plans to part-privatise Royal Mail three years ago and after the proposal was ditched by the former Labour administration.
Former prime minister Gordon Brown's Labour government scrapped the sell-off plans in 2009 as Britain struggled with recession following the global financial crisis.