NIAMEY (Reuters) - Niger, struggling to keep Islamist movements from spilling in from its north and south, wants to start joint military patrols along its border with Nigeria, the government said.

The West African state has so far managed to avoid a rebellion that split neighboring Mali in two, but is now worried about Islamist fighters from Nigeria's Boko Haram sect to the south.

"Our cooperation must be reinforced by starting joint patrols along the border, which have been planned but delayed," Niger Justice Minister Marou Amadou said on state television late on Saturday after a meeting with Nigerian officials.

"Niger is determined to combine its efforts with others... to face the threat that al Qaeda and Boko Haram pose for security in our countries," he said.

Niger and Nigeria have been debating the possibility of joint patrols along their 1,500-km (900-mile) border since 2008, but have yet to start them even with Boko Haram now waging a low-level insurgency against Nigeria's government.

Boko Haram, whose name translates roughly to "Western education is bad" in the local Haussa language, wants to carve an Islamic state out of Nigeria, and has been blamed for hundreds of deaths in bombings and shootings.

In Mali, a Tuareg separatist rebellion early this year was hijacked by rebel groups linked to al Qaeda, seeking to impose a strict version of sharia (Islamic law).

Since January, Niger - one of the world's poorest and least developed countries - has reinforced its border operations to keep such instability from spilling over.

Some 3,000 Nigerien troops were deployed along the northern border with Mali, Algeria and Libya and special forces units along the southern border with Nigeria.

Niger also uses aerial surveillance to police its vast and uranium-rich northern desert, where al Qaeda's north African wing is known to operate, officials said.

At the end of September, Niger security forces arrested five people suspected of being Boko Haram operatives in the Zinder region bordering Nigeria.

A military official told Reuters that Boko Haram members try to cross the border nearly daily but that they are likely transiting toward rebel-occupied northern Mali instead of setting up camps in Niger.

(Reporting by Abdoulaye Massalatchi; Writing by Richard Valdmanis)