The new reform proposal that Greece submitted to the institutions representing its creditors on Tuesday is not sufficient to strike a deal that would unlock new funding for cash-strapped Athens, three European Union officials said.

"What has been submitted is not sufficient to move the process forward," one EU official told Reuters.

"It is not sufficient and not acceptable to member states, I would say," a second official said.

The chief spokesman for the European Commission, which received the Greek proposal, reiterated after their comments that the EU executive was studying the suggestions and stressed that other EU officials "do not speak for" the Commission.

The spokesman, Margaritis Schinas, earlier told reporters that the Commission, along with the European Central Bank and IMF, was assessing the Greek suggestions "with diligence and care" and declined to comment on the nature of the proposal.

The second official who spoke on condition of anonymity said the new Greek proposal did not contain any solution to a dispute over pension reform between Athens and its creditors. It also contained proposals on debt restructuring that the creditors could not accept.

Greece has signaled that it wants to restructure its huge public debt through cheaper refinancing, longer maturities, a write-off of some principal and turning some debt into perpetual or GDP-linked bonds, but the plans have no support in the euro zone so far.

Other officials said the Greek proposal was divided into two documents, one of which addressed mainly fiscal issues like the size of the primary budget surplus and the other spelled out Athens' ideas for a major debt restructuring.