15 people, including Fiji Labour Party members, are currently being questioned at the Lautoka Police Station.
FBC News reports police have confirmed making the arrests last night.
The Fiji Labour Party leader, Mahendra Chaudhry, says he has been told the 15 are awaiting a police decision on whether they should be charged with holding a meeting without a permit.
He says the group was having a yaqona session at a private residence when police barged in.
"The Labour Party had not scheduled any meeting in that area. So this is just plain intimidation and harassment of Labour Party activists and supporters as far as I can see."
Mahendra Chaudhry says he questions how the country can move towards a new constitution if police behave this way.