The military regime already has ruled out Suu Kyi's participation on the grounds that she married a Briton, who has passed away. She has been under house arrest for more than a decade as leader of the National League for Democracy.

The verdict putting Suu Kyi under house arrest for a further 18 months was an embarrassment for Ban, who last week said he expected a positive and timely response from the military regime in Yangon to his demand for the release of Suu Kyi and Myanmar's political prisoners.

Ban issued the demand for the political prisoners' freedom after meeting with the Groups of Friends on Myanmar, composed of some Asian and Western nations, in anticipation of Monday's verdict.

Suu Kyi was found guilty of harbouring an American in her residence in violations of terms of her house arrest.

'The secretary general urges the government to immediately and unconditionally release Daw Aung San Suu Kyi and to engage with her without delay as an essential partner in the process of national dialogue and reconciliation,' Ban's statement said.