* Syrian opposition says 13 million need help
* Russia, China have blocked past resolutions against Assad
* Hollande discusses humanitarian situation with opposition (Adds Hollande, second diplomat)
By John Irish
PARIS, July 24 (Reuters) - Diplomats have started exploring whether they could get enough votes to pass a U.N. Security Council resolution to help aid groups get into Syria as the death count mounts, a French diplomatic source said on Wednesday.
Syria's civil war has killed more than 100,000 people and left millions homeless.
France's foreign minister said on Monday the Security Council, which has been deadlocked over how to respond to the war, needed to tackle the humanitarian crisis.
"There are ideas that are still being worked on to see if, at least on the humanitarian side, it would be possible to have a resolution on access," the French diplomatic source said.
"At this stage it is a reflection, but it's not certain it will lead anywhere," the source added without specifying what access would entail.
Veto-wielding Security Council members China and Russia have already blocked three resolutions backed by the United States and European powers aimed at sanctioning Syrian President Bashar al-Assad.
Moscow, Assad's main arms supplier, has also indicated it would not support any resolution opening up "safe zones" or "humanitarian corridors" in Syria, suggesting the West could use them as an excuse to intervene in the conflict.
A DYNAMIC CRISIS
French President Francois Hollande met the newly elected head of the opposition Syrian National Coalition (SNC) in Paris on Wednesday and said he stood by the organisation.
France was working on political and humanitarian aspects of the crisis as well as "corridors that could be opened to support the population," Hollande said.
After Hollande's meeting with SNC head Ahmed al-Jarba, a second French diplomat told Reuters there was currently "zero chance" of getting an agreement on humanitarian corridors.
"But having said that the crisis is dynamic, is developing. There are options that disappear and others that emerge," the diplomat added.
The Council will hold an informal meeting with members of the opposition Syrian National Coalition (SNC) on Friday to discuss humanitarian access, how to end the violence and other issues, Britain's U.N. envoy said on Tuesday.
Suhair al-Atassi, vice president of the coalition who is in charge of its Aid Coordination Unit, told reporters earlier on Wednesday 13 million people needed help.
"There is a big gap between the humanitarian needs on the ground and what the different donors give ... There is a lack of everything inside Syria now," said Atassi in Paris.
"It's not just essential needs such as flour, tents or food, but also infrastructure in liberated zones where the Syrian state has to be rebuilt," she added.
France, which has so far given about 170 million euros in aid, has been one of the few countries to funnel its cash through the coalition's aid unit since it was set up last year.
Atassi said the coalition was planning to set up a transitional government at a meeting on Aug. 3-4 - a move that would bolster its legitimacy as it moved to replace Assad's government. (Reporting By John Irish; Editing by Andrew Heavens)