A Myanmar army officer has been jailed for two years after he signed a petition supporting Aung San Suu Kyi's efforts to reduce the military's role in politics, a member of her opposition party said Monday.

Kyar Swar Win was arrested in July after pictures circulated online apparently showing him signing up to a campaign run by Suu Kyi's National League for Democracy party aimed at ending the army's effective veto in parliament.

Last Friday a military court in Pyin Oo Lwin, near the central city of Mandalay, found him guilty of breaking military law by "not following orders and discipline", according to local NLD MP Kyaw Thiha.

He said the father-of-two was handed a two-year sentence and stripped of his rank as major for the rare act of dissent from within the military, which for almost half a century ruled the country with an iron fist.

"His wife said her husband always admired Daw Aung San Suu Kyi and also didn't want to be in the army any more," Kyaw Thiha told AFP. Daw is a term of respect.

Suu Kyi's party is campaigning to remove the army's effective veto on changing the constitution, which bars the veteran activist from becoming president.

The country is grappling with the legacy of junta rule as it heads towards crucial parliamentary elections in 2015.

An NLD petition gained some five million signatures -- about 10 percent of the population -- but the party has since admitted that it does not have the power to push through changes in the face of army opposition.

Parliament has been gripped by fierce debates over the charter in recent weeks. The military has indicated strong determination to maintain its grip on the legislature, where it has a quarter of the seats.

Parliament will choose the next president after next year's polls, but Suu Kyi is currently ineligible for the top post under the junta-drafted constitution.

It rules out anyone with a foreign spouse or children and Suu Kyi's late husband and two sons are British.

Any vote to change that clause, or other key sections, requires a majority of more than 75 percent -- giving soldiers the final say.