Cambodia's foreign minister called Mr Broderick's remarks unacceptable

The Cambodian government has threatened to expel a United Nations envoy, accusing him of "unacceptable interference" in the country.

The warning came after the UN called for "a transparent and participatory" process as parliament debated an anti-corruption law.

Human rights and opposition groups say the law is deeply flawed.

Monitoring groups routinely list Cambodia as one of the most corrupt countries in Asia.

In the latest spat, Foreign Minister Hor Namhong sent a letter to the UN resident coordinator, Douglas Broderick, complaining about what he called "flagrant and unacceptable interference in the internal affairs of Cambodia".

This was a reference to a statement released by the UN on 10 March, just before the anti-corruption law was passed by parliament, calling for more public discussion.

Mr Broderick had noted that "no draft law has been shared with interested stakeholders, including civil society, since 2006".

The foreign ministry accused Mr Broderick's office of exceeding its mandate.

"Any further repetition of such a behaviour would compel the Royal Government of Cambodia to resort to a 'persona non grata' decision," it said in a letter dated 20 March.

Opposition and rights groups, which walked out of the vote for the anti-corruption law, said it was flawed and inadequate.

A national anti-corruption council and an anti-corruption unit will be created to oversee investigations - both of them appointed and controlled by the ruling party.