Eurozone nations on Thursday gave themselves until September to agree a long-delayed financial transactions tax despite British opposition.
The plan was first proposed in 2011 to force banks and investment houses to pay for the excesses which led to the 2008 financial crash and the eurozone debt crisis but has been mired in disagreements ever since.
On Thursday, 10 eurozone countries decided that enough progress on agreeing the tax had been achieved to merit a few more months of negotiations.
"There are two technical questions that still needed to be addressed," said Finance Minister Hans-Joerg Schelling of Austria, the country leading the negotiations.
"It is clear to everyone that if there is no solution in September we will probably not find one," he added.
The proposed tax has strong backing from Germany and France, the eurozone's top economic powers.
But the talks have dragged on amid still unresolved quibbles over the scope of the tax, which financial products would be affected and at what rate.
Supporters of the tax argue it can help avoid a repeat of the failings of the financial markets which plunged the world into crisis in 2008.
France, Germany, Austria, Belgium, Greece, Italy, Portugal, Slovakia, Slovenia and Spain back the tax.
Britain is vehemently opposed to the tax as it fears it will apply to transactions that originate in its City of London global financial hub, meaning for instance that a British bank trading with a German bank would have those transactions taxed.
Blocking the ability of eurozone members clubbing together and forcing decisions on Britain has become a hot issue in the referendum on the UK's membership in the 28-member bloc to be held next Thursday.