An Israeli court has charged Mordechai Vanunu with violating the terms of his release from jail last year.
Vanunu has tested the authorities since his release
The charges relate to the former nuclear technician's interviews with foreign media and defying a travel ban.
But he told Reuters news agency he would continue speaking to the press, despite the charges.
Mordechai Vanunu served 18 years in jail for disclosing details of Israel's nuclear programme, and was released in April under strict conditions.
He has not been arrested and Israeli officials say they are not aware of any plans to take him into custody.
The Christian convert was briefly held over Christmas after attempting to go to the West Bank town of Bethlehem.
Israel insists Vanunu still poses a security threat and he is banned from leaving Israel - including visiting the West Bank and Gaza Strip - or talking to foreigners without permission.
But he has given several interviews to foreign media, including the BBC.
He denies passing on classified information about the Dimona nuclear plant where he used to work.
Now living in Jerusalem's St George's Anglican cathedral, Vanunu is banned from using the internet or mobile phones, and may not approach embassies or borders.
Israel's justice ministry charged Vanunu with 21 counts of violating the restrictions, some of which are due to expire next month.
"They can charge me 50 times if they want," he told Reuters.
"The police are just following procedure," he said.
"I have not been charged with harming national security but with not respecting the restrictions on me," Reuters quoted him as saying.
"I am still hopeful they will end my restrictions."
In May 2004 - a month after his release - he gave his first interview to the BBC, through an Israeli journalist.
He said he had spoken out to prevent a nuclear holocaust.
Vanunu was kidnapped in Italy by Israeli agents in 1986 following a Sunday Times article, based on an interview with him, which exposed Israel's atomic secrets.