For the first time, a majority of Ukrainians support the idea of joining NATO and the president this week spoke of putting the idea to a popular vote, but experts say it still remains a distant dream.

President Petro Poroshenko, who a decade ago described the promise of eventual NATO membership as "the light at the end of the tunnel", said Monday it would take several years of reforms before Ukraine could become a candidate.

But the new coalition government plans a first step -- dropping its official "non-aligned" status -- in a matter of weeks.

It is including the long-term wish to join the Western security alliance in its official programme, and Poroshenko said voters would eventually decide the issue in a referendum.

Until recently, polls have consistently shown most Ukrainians would rather stay away from the alliance and out of the crossfire between Russia and the West.

But with reports of Russian troops and weaponry pouring over their border to support the separatist rebellion in the east, the tide of opinion has swung dramatically.

A poll this month found 51 percent in favour of joining NATO, up from just 20 per cent a year ago. Only a quarter are now opposed.

The numbers have risen steadily since Russia annexed Crimea in March.

"(Russian President Vladimir) Putin's actions are the main cause of the mood change in Ukraine towards NATO, perhaps even the only one," said Andriy Bychenko, a sociologist at the Razumkov Centre in Kiev.

- 'Fluffing his feathers' -

However popular, experts see little chance of Ukraine entering NATO any time soon.

"This was just posturing by Poroshenko -- trying to fluff his feathers in front of Russia," said Janek Lasocki, a Ukraine expert at the European Council on Foreign Relations, of the president's referendum promise.

"There are many reasons why it's far off. For a start you need secure borders to join NATO and that is clearly not the case."

Although there are no hard-and-fast criteria for membership, Ukraine would need to realise vast improvements in its corrupt and ill-equipped army to make the grade.

German Foreign Minister Frank-Walter Steinmeier underlined the obstacles this week, telling Der Spiegel weekly: "I see Ukraine having partnership relations with NATO, but not membership."

Even with the recent surge in support at home, Lasocki said, trying to join the alliance would also be highly divisive at a time when the government is struggling to reassure its Russian-speaking minority and unite the country.

"A lot of people want to move towards Europe -- including in Russian-speaking areas -- because they want European standards. They want heating in their schools and less corruption in their government, but joining a military alliance is a whole other matter."

- Russian anxieties -

Ukraine has long been considered a possible candidate for NATO, signing a partnership agreement in 1997 and launching talks on full membership in 2005.

But that process spooked Russia, which pressured the previous pro-Kremlin government in Kiev into pulling out of the talks in 2010.

Indeed, many see the current collapse in East-West relations as rooted in Russia's fear that the West is pushing into its traditional sphere of influence.

Its efforts to destabilise Ukraine mirror the war it launched in Georgia in 2008 -- a move that similarly scuppered that country's efforts to join NATO.

A spokesman for President Vladimir Putin last week told the BBC that Russia needed "a 100 percent guarantee that no one would think about Ukraine joining NATO."

That triggered a stern rebuke from NATO, which described the demand as "out of touch with reality" and in breach of international agreements that give every country the right "to choose its own security arrangements".

But in the end the West knows that solving the conflict will mean soothing Russian anxieties, says Alisa Lockwood, a senior analyst at IHS Country Risk in London.

"If a resolution to the conflict is to be reached -- which the EU seems to be increasingly pushing for behind the scenes -- Russia will need to be reassured that Ukraine is not going to be joining NATO in the near future, if at all," she said.

In any case, she said the idea of a referendum was just a way "to put off the issue while continuing to pay lip service to NATO membership for the sake of the domestic audience."

"Much may have changed in Ukraine by that point and it is not guaranteed that Poroshenko himself will be in power, so whether the referendum ever takes place is an open question."