A coalition of some 30 Cambodian non-governmental organisations have expressed concern over what they say is the ruling party's use of the judiciary against opposition parties ahead of national elections in July.

The Action Committee coalition says the judiciary is being used to prevent politicians from participating in the poll.

Correspondents say court cases are currently pending against two prominent opposition figures, including a criminal lawsuit filed against main opposition leader Sam Rainsy by the foreign minister, Hor Nam Hong.

Earlier this week, the US ambassador to Cambodia said he was also concerned the suit filed against Sam Rainsy could have an affect on the general election.

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