Burmese authorities have sentenced four opposition members to prison for campaigning against the military government's new constitution.

A spokesman for the National League for Democracy, Nyan Win, told reporters Friday that all four were sentenced last month to one year prison terms. He said the activists were arrested in March for distributing leaflets urging voters to reject the constitution, which was drafted by the military government.

The government claimed an overwhelming victory in the referendum on the constitution held in May, days after a devastating cyclone left nearly 140,000 people dead or missing and more than two million others homeless.

Win said 14 other party members who were arrested on June 19, the birthday of party leader Aung San Suu Kyi, are still in detention.

Aung San Suu Kyi has been under house arrest for 12 of the past 18 years.

The opposition rejects the charter, saying it solidifies the military's hold on power. The country's military leadership says the document is part of a seven-step roadmap to democracy, leading to multi-party elections in 2010.

Some information for this report was provided by AFP and Reuters.