JAKARTA: Nine years after a tsunami devastated the province of Aceh and drove its separatist chieftains to the negotiating table with Indonesia, rebel symbolism is back in vogue in the country's westernmost province.

A decision in March by Aceh's year-old regional government to gazette the flag of the former separatist movement, GAM, as the official flag of the province has stirred up old animosities and posed questions about the future.

The central government has given Aceh's leaders until Tuesday to reverse the flag decision under threat of having it overturned. But Jakarta is likely to realise that heavy handed action could reopen the wounds stitched closed across a negotiating table in Helsinki in 2005.

Back then, Aceh was given special privileges — including its choice of flag — which are not afforded to other regions of Indonesia. In return, a 30-year armed separatist struggle ended. 

But Aceh's move now to adopt the crescent-and-star flag is literally a red rag to the national bull.

As a vast ethnically and culturally diverse country, any threat, even symbolic, to Indonesia's motto "Unity in Diversity" is taken very seriously indeed. The loss of East Timor in 1999 still stirs national resentment and the country fights hard to contain a separatist movement in West Papua. There, too, flags are an issue.

In 2007, the Indonesian government passed a regulation specifically prohibiting provinces adopting separatist symbols.

To the governor and deputy governor of Aceh, former leaders of GAM, Zaini Abdullah and Muzakir Manaf, this is a test of what Aceh's special deal with Indonesia really means.

The preamble of the agreement which brought about peace in 2005 said it was signed because "only the peaceful settlement of the conflict will enable the rebuilding of Aceh after the tsunami disaster on 26 December 2004".

The rebuilding task has been a success. With the help of national and international funds, Aceh's physical infrastructure has recovered, it held a largely peaceful election and transition of government last year, and it has developed its own distinctive political culture (based on a strict and often controversial application of Islamic sharia law). It remains poor, but is participating in the economic life of the country.

Now it's clear that differing expectations about the extent of Aceh's power were baked into the 2005 accords.

According to ANU academic Ed Aspinall, Aceh's position on the flag "can be seen as a deliberate move to challenge … to test the limits of their autonomy".

In 2005, the negotiators on the Indonesian side believed they had achieved a relatively tame Aceh, governed by "special autonomy [the law under which Papua is also governed] with a few new clauses",

Professor Aspinall says. The GAM negotiators, by contrast, believed they had achieved something akin to self-government.

The flag issue was, perhaps deliberately, left ambiguous.

Even at the time it was a bone of contention. GAM commander Sofyan Dawood said during negotiations that the "the flag of Aceh is the moon and star flag as used by GAM", but government negotiator Sofyan Djalil said the Aceh flag could "not be like the GAM flag.

The flag issue may also be a signal that Aceh's government will begin kicking against the traces of the 2005 deal in other, more important areas.

Behind it is a nascent fear in Aceh that the peace deal did not deliver much more autonomy than most other regions enjoy. This has become clear as Aceh tries to develop a new plan for the use and exploitation of its vast and fauna-rich forests. As Aceh favours more development, and Jakarta shapes to block it, the region's lawmakers are becoming painfully aware of the limitations of their power