* Aid workers hoping for more open approach to food crisis
* Junta acknowledges extent of hunger threat
* Famine would threaten transition
By David Lewis
NIAMEY, March 2 (Reuters) - An acknowledgement by Niger's new military leader that millions face hunger is a policy volte-face for the West African state that may help it avert famine and even worse instability.
Major Salou Djibo, who ousted President Mamadou Tandja in a coup on Feb. 18, has said that all means would be available to deal with a crisis that aid workers warn will leave millions hungry and over 200,000 children with severe acute malnutrition.
The alarm contrasted with Tandja's handling of previous crises. In 2005 he denied people were hungry until media attention made the position untenable.
Aid workers say Niger is now better prepared but they still complain of facing obstacles in trying to tackle the situation in the desert state, one of the world's poorest despite winning billions of dollars of investment in its uranium and oil wealth.
"It could be a strategy to show that there has been change," Severine Courtiol Eguiluz, a senior programme manager for Save the Children in Niger, said after Djibo's statement on Sunday.
"This could make it easier (for us) to work," she added. "It was complicated before to speak about the food situation ... It limited our capacity to lobby. This was a handicap because we need to be able to speak about it."
Aid workers in the country ranked by the United Nations as the world's least developed say they faced delays as the government under Tandja did not always accept the data underpinning the support plans they presented.
Since the coup, the military rulers have accepted U.N. estimates that at least 200,000 children face severe acute malnutrition, a status that requires hospitalisation. Previous government figures stood at 36,000.
The U.S.-funded Famine Early Warning Systems Network warned that 2.7 million people this year would be "extremely food insecure", a term covering stages from missing meals to malnutrition and famine -- after rains failed in many regions.
Another 5.1 million of Niger's estimated population of 14 million would have under two months of food supplies after the lowest per capita cereal production for 20 years, it added.
The international community wants Djibo, who appointed a 20-member transitional government on Monday, to concentrate on holding elections for a democratic government. But that goal could be threatened if food insecurity is not addressed.
"It is in everybody's interest to manage the food situation because the success of the transition may hinge on it," said Moussa Tchangare, coordinator for Nigerien civil society group the Consortium for the Right to Food in the Sahel.
"The whole transition process could collapse if the food security aspect is neglected ... Millions of people risk not having food and if that is not well managed all other things would become second priority," he said.
Few aid workers have used the term famine and most also say it is too early to make a clear judgement on the new leaders. But there is optimism that they will be supportive of aid plans.
"We have started to advocate for a better response plan and it seems to have been heard," said Anne Boher, a spokeswoman for UNICEF, the U.N. Children's Fund.
Humanitarian aid was not cut when donors froze development help after Tandja changed the constitution to clear his way to stay in power after his second elected term ran out in December.
Aid workers also say this year's crisis may be comparable in size to 2005, but the government has added more hospitals and feeding centres, and trained more staff since then.
Yet citing the harsh environment, climate change and demographic trends -- Niger has one of the highest fertility rates in the world with over seven children per mother -- aid workers stress Niger's is a long-term problem.
"We need to react immediately but unless we do something in the long-term it will happen again...we'll be in this situation in three years again," Save the Children's Eguiluz said.
Additional reporting by George Fominyen in Dakar; Editing by Daniel Magnowski