Jammu and Kashmir Liberation Front (JKLF) chairman Yasin Malik was on Monday detained by the police in Batamaloo area of Srinagar.
The arrest took place when he was on his way to meet Hurriyat leader Syed Ali Shah Geelani.
As per reports, Malik was scheduled to take part in a joint meeting of resistance groups at the Hurriyat (G) chairman's residence.
Malik was arrested by the police earlier on June 17 when he was en-route Anantnag for addressing an election boycott rally. He was, however, released the next day.
The separatists have called for boycotting the upcoming by-elections in Anantnag constituency from where Jammu and Kashmir Chief Minister Mehbooba Mufti is contesting.
Asserting that this election process is against the interests of Kashmiris, Malik had earlier urged the people to keep away from the by-polls to be held in holy month of Ramadan.
The seat was left vacant after the death of former chief minister Mufti Muhammad Sayeed.