Mr Capriles has been at the forefront of efforts calling for a recall referendum on President Nicolas Maduro.
There was no immediate comment from the government.
The ban comes after a week of several large opposition-led protests in the capital Caracas. They accuse the government of stifling dissent.
On Thursday a man was shot dead during the demonstrations.
Over the last few days, authorities have accused Mr Capriles of inciting violence and bloodshed by leading protests against the unpopular president.
The protesters were demonstrating against a decision by the Venezuelan Supreme Court to assume control of the opposition-led congress.
Although the court's decision was quickly overturned, the street protests continued.
Mr Capriles, who is a former presidential candidate and the governor of the state of Miranda wrote on social media: "URGENT: I inform the country and international public opinion that I am being notified at this very moment of a BAN for 15 years."
He accused the government of running a smear campaign against him.
Venezuela: What's behind the turmoil?
The most expensive Nutella in the world
Leopoldo Lopez loses appeal
In 2015 another prominent opposition leader, Leopoldo Lopez was sentenced to nearly 14 years in prison on charges of inciting violence during anti-government protests in 2014.
Mr Lopez was himself barred from office in 2008 when he was the popular mayor of a Caracas district.
The Venezuelan president, Nicolas Maduro, narrowly defeated Mr Capriles in the 2013 elections, a result that sparked controversy and debate as the opposition claimed electoral fraud.
Mr Maduro's government have said that a US-backed business elite is responsible for Venezuela's economic downturn and that it was trying to organise a coup to impose right wing rule.

The government-proposed changes to national security laws are part of a review into counter-terrorism.
The new measures would mean the Australian Defence Force (ADF) could be called in sooner to help police deal with threats.
They were prompted by criticism of the speed with which police responded to the 2014 siege in a cafe in Sydney.
Current legislation prevents police from calling on the ADF until they have reached the limit of their capability or capacity.
Under the new measures, the military would also provide specialised training to police forces.
At a press conference, Australian Prime Minister Malcolm Turnbull said he was "taking a lot of the red tape and the gum out of the works to enable the cooperation between the police and the ADF".
Two hostages and the lone gunman died in the Sydney siege and earlier this year a coroner said that the authorities had been too slow to respond
How the Sydney siege unfolded
Australia has seen several Islamist-inspired attacks over the past years, prompting a review of how police and authorities can respond better.
In the most recent case, a terrorist holding a hostage in Melbourne was killed by police last month.

St Mary's Church in Llanfair Kilgeddin, between Abergavenny and Raglan, was targeted between 2 and 3 August.
An oak door, valued at about Â£1,000, was damaged, along with four oil lamps dating back 300 years. Metal organ pipes and a brass plaque were stolen.
Matthew Saunders, director of Friends of Friendless Churches, said: "They left it looking like a bomb landed."
Gwent Police is investigating the theft and Mr Saunders said he thought thieves were targeting metal inside the building.
"It's completely absurd because the metal is worth practically nothing," he said.
"We're very upset by it, but we will not be deterred from opening the church."
Friends of Friendless Churches saved St Mary's from closure when it took over in the late 1980s. The building is medieval in origin.
Mr Saunders said the total value of the theft and damage was not fully known, adding: "It's both petty and monstrously disrespectful."
A decision on what to do about the missing pipes from the mid-19th Century organ will be taken when the church committee meets in October.
A leading Venezuelan opposition leader, Henrique Capriles, says he has been formally banned for 15 years from political activity.
[NEXT_CONCEPT]
The Australian military is to be given broad new powers to respond to domestic terrorist attacks.
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"Monstrously disrespectful" thieves have wrecked and ransacked a church in Monmouthshire.