The call by Indonesia's Immigration Department highlights the country's paranoia about foreign media scrutiny of affairs in the restive province.

Local police also say they are still investigating Thomas Dandois, 40, and Valentine Bourrat, 29, for the possible criminal charge known as makar, which can be translated as treason or subversion.

The two, who were working on a documentary for the French TV station Arte, have been in police custody since their arrest on August 5. They were caught in the highlands town of Wamena working while on a tourist visa.

Indonesia insists reporters gain a journalist's visa, plus  difficult to obtain permission to travel to West Papua.

In most cases, journalists caught without a valid visa are simply deported.

The head of the Immigration Office in Papua, Garda Tampubolon, told Fairfax Media that the French documentary maker and camerawoman would remain in custody until the start of their trial, which he hoped would be in October.

"It's our wish that they get the maximum penalty [of five years] but . . . everything depends on the panel of judges," Mr Garda said.

Police spokesman Sulistyo Pudjo said the criminal subversion investigation was under way but "this is a very complicated case, it is not easy".

The charge carries a 20-year jail sentence.

Police have indicated in the past that Dandois and Bourrat are under suspicion over an ammunition swap gone wrong in the Papua highlands, during which two police officers were shot.

However, the only evidence of their alleged involvement appears to be that they interviewed political separatists.

The incident took place on July 28, two days before the reporters landed in Sorong, West Papua.

Mr Sulistyo said police were suspicious that the two may have been acting under the orders of exiled independence leader Benny Wenda because "there were some SMSs telling [the reporters] to come here".

The Indonesian government is sensitive about the Britain-based Mr Wenda, against whom they once issued an bogus Interpol arrest warrant, which has since been overturned.

Through their lawyers, the reporters have apologised for breaching Indonesia's immigration laws. Their production house, Memento, has guaranteed it will not "produce or distribute material which may discredit Indonesia's reputation on the international stage".

The Indonesian journalists' union, AJI, and the Press Council have both called for the reporters to be released and then deported.

AJI head Eko Maryadi said the detention of the journalists was "not in line with the climate of press freedom which president Susilo Bambang Yudhoyono always speaks of".

Treating Papua differently from the rest of Indonesia would "just give the impression that something wrong is going on there, that there is something the government attempts to cover up", he said.