Officials from some 170 countries gather in Bonn from Monday to lay the groundwork for a new global warming pact, as Europe pushes for progress amid fears of political and financial wavering.

Teams of experts and diplomats will seek to outline a work plan for clinching a new deal by 2015 on limiting Earth-warming gas emissions, but observers fear squabbling and political inertia may hamstring negotiators.

"A lot of other issues are competing for space and time," climate change observer Alden Meyer told AFP ahead of the May 14 to 25 talks. "It all comes down to politics and national interests."

The gathering is the first since UN member states agreed in Durban, South Africa, last December to bring all major greenhouse-gas emitting countries under a single legal roof from 2020.

Since then, anger has been brewing over Europe's imposition of a carbon emissions tax on international airlines from January 1 -- which countries like India and the United States have warned could derail talks.

There is also discord between rich and poor nations about how much proportional responsiblity each should bear for curbing greenhouse gases.

"We must continue to move forward," European commissioner for Climate Connie Hedegaard urged this week at a meeting of European nations, least-developed countries (LDCs) and the Alliance of Small Island States (AOSIS).

"We need to be more ambitious, not less, so we need more people on board," she said.

Observers say geopolitical realities are tying the hands of countries like the United States, which will hold presidential elections this year, and Japan which is dealing with the economic fallout of last year's tsunami and nuclear melt-down.

"The US doesn't want to be talking about putting more money on the table before the presidential election," said Meyer, policy director for the Union of Concerned Scientists watchdog body.

"If there is no sense from developing countries that the northern countries are serious about the financial pledges that they made ... that will make them dig in their heels on a lot of other issues and that will make progress very difficult," he warned.

Hedegaard had also urged rich countries to deliver on promises of finance to aid developing nations emission-curbing efforts, adding: "we need not to underestimate the risk of back-tracking."

The Bonn talks will seek to lay the groundwork for the next UN climate conference in Doha in November and December, where countries must formally adopt an amendment to the Kyoto Protocol on climate change.

This as scientists warn that the target agreed at the chaotic Copenhagen summit of 2009 to limit global warming to two degrees Celsius (3.6 degrees Fahrenheit) from pre-industrial levels, could be missed.

Wendel Trio, director of Climate Action Network Europe, a coalition of non-governmental climate bodies, said expectations for the Bonn talks were "low".

"Countries have different positions on what to do, he said.

"Some countries like AOSIS, the LCDs and the EU want to start working ... and get agreement on a work plan as soon as possible, while others such as the US and India prefer to only have some brainstorming and not engage in any negotiations."

France's climate ambassador said the United States and China were adopting a "wait-and-see" attitude to climate talks.

Last month, US climate envoy Todd Stern told journalists that 2012 "ought to be devoted to a kind of conceptual phase".

Meyer warned of a "dire picture" for the planet that required a sense of urgency.

"Political will is not keeping up with the physics in the atmosphere," he said.