By Ed Cropley

BANGKOK (Reuters) - Nearly 1,000 bra makers protested outside the German embassy in Bangkok on Tuesday in a labour dispute stemming from the vexed issue of whether Thais have the right not to stand up in honour of King Bhumibol Adulyadej.

The workers chanted slogans accusing the bosses of Body Fashion, part of German lingerie firm Triumph International, of unfairly sacking union leader Jitra Kotchadej after she wore a T-shirt questioning the convention of rising for the royal anthem before movies.

According to the union, 36-year-old Jitra was sacked in July for wearing a T-shirt saying "Not standing is not a crime; different thinking is no crime" while on a television discussion about abortion rights.

Although innocuous enough to the outsider, the slogan is an explicit reference to an unprecedented campaign questioning the semi-divine reverence in which many Thais hold the king.

In the case that sparked the campaign, Thai police in April formally accused 27-year-old Chotisak Oonsong of lese majeste, or insulting the monarchy, for refusing to stand when the royal song and video aired before a movie screening.

Chotisak said he was only exercising his constitutional right to freedom of expression, but risks up to 15 years in jail under the southeast Asian nation's draconian lese majeste laws.

The charge, which is open to abuse because it can be levelled by anybody, has become a common feature of the poisonous political atmosphere that has followed the openly royalist 2006 coup against then-prime minister Thaksin Shinawatra.

Thaksin's opponents, a monarchist group called the People's Alliance for Democracy, jumped on Jitra's television appearance and threatened a boycott of all Triumph products unless she was given the boot.

The company complied, and has refused to reinstate her even though Jitra says she was unaware of the slogan's significance.

"It was just another campaign T-shirt that I wore to help my activist friends," she told Reuters.

In a statement, Body Fashion accused Jitra of "engaging in highly public and controversial political activity on TV" and said it had fired her, in accordance with labour laws, for damaging its reputation and business.

Bhumibol, 80 years old and the world's longest-reigning monarch after six decades on the throne, has said he should not be above criticism, although few have dared to take the risk.

(Additional reporting by Nopporn Wong-Anan)

(Editing by Darren Schuettler and Valerie Lee)