By Deutsche Presse Agentur
After the arrest in Langkon in north-eastern Malaysia, Maria Chin Abdullah - chairman for The Coalition for Clean and Fair Elections(Bersih 2.0) - was taken to Kota Marudu police station for questioning and later released on bail, the statement said.
The group hopes to encourage Malaysians to stand up to perceived government abuses of power and corruption, and to demand electoral reforms, a freer press and stronger public institutions.
Bersih 2.0 has stages large-scale rallies demanding institutional reforms and the resignation of the prime minister.
Najib has been at the centre of a corruption scandal since July 2015, when a report suggested that 673 million dollars in the prime minister's personal bank accounts had been siphoned off from a beleaguered state fund.