Myanmar's supreme court is to hear an appeal against the house arrest of Aung San Suu Kyi, the country's opposition leader, after she was sentenced to a further 18 months in detention.

The court did not release a date for the hearing, but Nyan Win, Suu Kyi's lawyer, said he expected to present the case within a month.

Lawyers are appealing the 64-year-old democracy leader's house arrest, which she received for sheltering a US intruder who swam to her lakeside home.

Suu Kyi was initially sentenced last August to three years in prison with hard labour, but that sentence was commuted by General Than Shwe, Myanmar's junta chief.

The court said her actions broke a law protecting the army-ruled state from "subversive elements" and breached the terms of her house arrest.

But her lawyers say the law she was charged under can no longer be applied because it was part of the 1974 constitution, which was replaced last year.

Critics have dismissed Suu Kyi's house arrest as an attempt to keep her in detention ahead of next year's elections, which will be Myanmar's first in two decades.

Suu Kyi has spent 14 out of the last 20 years in detention, since her party swept the last elections in 1990 - a victory that was never honoured by the military, which has ruled the country since 1962.