BANGKOK (AFP) - This year's US$1 million (S$1.25 million) Thailand Open has been cancelled because of the deepening political crisis in the divided kingdom where martial law was declared on Tuesday, organisers said.

The OneAsia tournament was meant to have taken place at Bangkok's Thana City Golf & Sports Club in March but was postponed after a 60-day state of emergency was declared in the capital.

The event was due to be rescheduled but organisers said late on Monday that it would not take place in 2014, with hopes it will return to the calendar next year.

"The Thailand Open is a world-class tournament and we want to hold it when the environment is stable," president of the Thailand Golf Association Rungsrid Luxsitanonda said in comments released by the organisers.

Thailand's army early on Tuesday imposed martial law to quell unrest across the country, which has been shaken by deadly violence since anti-government demonstrations erupted six months ago.

The army said the move was "not a coup" - in a country which has seen 18 actual or attempted military takeovers since 1932.

The political crisis has its roots in the 2006 ouster of tycoon-turned-premier Thaksin Shinawatra, who went into self-imposed exile to avoid jail for a corruption conviction.

Patrick Feizal Joyce, a vice-president at event promoter World Sport Group said: "We needed some certainty in the situation so it has been agreed by all relevant parties to cancel this year's Thailand Open.

"It is our hope that the tournament will be staged next year," he added just hours before martial law was invoked.

Last year's Thailand Open was won by Thai Prayad Marksaeng.