The five were told to appear at the Phnom Penh Municipal Court for questioning later this month, and could face at least 14 years behind bars if found guilty at trial, The Cambodia Daily newspaper reported.
The protests for a 60-dollar increase to the 100-dollar minimum wage began in December, but quickly swelled amid support from opposition politicians.
The protests were shut down by armed government forces in early January, with five people shot dead, and 23 unionists and garment workers arrested and subsequently convicted.
Unions are currently calling for an increase in the minimum wage to 177 dollars to reflect a rise in inflation.
Talks between government, manufacturing and union officials are scheduled to take place in October.
The charges come as unions plan a fresh campaign over pay, said Moeun Tola, head of the labour project for the Community Legal Education Centre, a Cambodian legal aid NGO.
DPA