BANGKOK Laos Wednesday threatened retaliatory measures against Thailand if it went ahead with the making of a historical film depicting a Thai heroine's battles against laotian invaders.

"The laotian authorities will react with measures that will depend on the extent of the film's effect on Laos and how badly it tramples the image of the laotian leader," said Ambassador to Thailand Hiem Phommachanh.

The Lao government has repeatedly said that "Tao Suranari," which tells the story of the eponymous heroine's victory over Laotian leader Chao Anuwong nearly 200 years ago, will harm relations between the neighbours.

It took up the matter with Thai Prime Minister Thaksin Shinawatra when he visited Vientiane in June, but the premier declined to take any action, saying that the film was being made by the private sector.

Hiem rejected the film's depiction of Laos' revered Chao Anuwong as an invader and said the project could jeopardise cordial relations between the two countries.

"The history of Thailand and Laos is intertwined, there have been times of friendship and times of trouble. When that trouble is brought up again in a film it could create problems," he told reporters.

The film project was initiated by Thai politican Korn Dabbaransi, leader of the chart Pattana Party. His constitutency of Nakhon Ratchasima, commonly known as Korat, was Tao Suranari's stronghold.

Suranari was the wife of a Korat ruler during the 1824-1851 reign of King Rama III.

She masterminded an ingenious plan to fend off the lao invaders, who were led by Prince Anuwong, by tricking them into drinking large amounts of alcohol and then launching an ambush.

Hiem said that in the version of the story told in Laos, there was no mention of Suranari at all.