The former Maldives president Mohamed Nasheed has defied a court order forbidding him from leaving the capital, Malé, after his trial on charges for abuse of power was postponed.

Nasheed, who resigned from office in February, later claiming he was forced to do so, is accused of illegally arresting a senior judge. Nasheed's trial was scheduled to start on Monday, but he said proceedings were cancelled without explanation.

The former president, who claims the charges are politically motivated, took advantage of the postponement to head to Maldives' southern islands to campaign, despite the travel ban imposed last week. "We have freedom of movement and there is nothing wrong [in what I are doing]," he told the Guardian.

He added that if police were to him it would backfire on the government led by Mohammed Waheed Hassan. "It would be folly for them to do that to a presidential candidate. If I cannot campaign, it says a lot about democracy."

The presidential election is scheduled for November next year but Nasheed says there should be an early poll to "restore democracy".

The former democracy activist and Amnesty International prisoner of conscience, was feted by the west –David Cameron described him as "my new best friend" – for his efforts to combat climate change after he became president in the Maldives' first multiparty elections in 2008. But the arrest of the judge led to widespread protests, and Nasheed lost the backing of the military and police, leading to his resignation, which he claimed was extracted at gunpoint.

An independent report by the commission of national inquiry found that the change of president was "legal and constitutional" and that Nasheed, had in effect, brought it on himself. The report was supported by Britain, the US and the Commonwealth, but Nasheed said it was a "whitewash" and had been criticised by others.

He described his impending trial as "trumped up charges in a kangaroo court", motivated not by justice but to "get at my head". Nasheed said he had not given the order for the judge to be arrested, adding that the decision was "within the bounds of the constitution".

He said: "To serve national security and have confidence in the judiciary we had to remove some very, very unreasonable people who were trying to defend the previous regime and work for their own interests."

Amnesty has described events in Maldives as a "human rights crisis", reporting beatings and arbitrary detentions of Nasheed's supporters by police acting with impunity.