Opposition leader Sam Rainsy has accused the Human Rights Party of trying to “break” his own Sam Rainsy Party and steal its members, even as the two parties remain in talks about a potential merger.

In a letter dated Monday, HRP president Kem Sokha wrote to Sam Rainsy to inquire about the terms of such a merger, which has been under discussion for months.

Kem Sokha asked whether Sam Rainsy supported an option entailing the merger of the HRP and SRP under a new banner, or a second option in which the SRP would subsume the HRP.

“We support the first option and see that this is an opportunity for a union of patriots and democrats to arrange a democratic movement for change,” Kem Sokha wrote.

In response, however, Sam Rainsy wrote in a letter to his own supporters that the HRP was using the same “tricks” employed by the ruling Cambodian People’s Party to undermine the SRP and induce defections.

Sam Rainsy has lived abroad since 2009 to avoid a lengthy jail term handed down against him last year in connection with a protest he staged along the Kingdom’s eastern border against alleged Vietnamese

encroachment. In recent weeks, Kem Sokha has appealed for SRP members to join the HRP, declaring last month that “the HRP will become the biggest opposition party in Cambodia if Sam Rainsy cannot return”.

Such rhetoric, Sam Rainsy said in his letter, is counterproductive in the face of the parties’ merger talks.

“Before choosing any FORMULA for a union, we must first show the required SPIRIT for a genuine and sincere union,” Sam Rainsy wrote.

“In fact, by adopting the CPP’s attitude toward us, the HRP is - willingly or not - serving the CPP interest and they have become a CPP de facto ally, at a time when the SRP is the main target for the CPP in the face of very serious national problems.”

In the 2008 national elections, the SRP won 26 seats while the HRP netted just three. Both opposition parties were dwarfed by the ruling party, which won 90 seats in parliament and serves as an effective rubber stamp for Prime Minister Hun Sen.

During a visit to the Kingdom last year, United States secretary of state Hillary Clinton encouraged the SRP and HRP to put aside their differences and form a united opposition against the ruling party.