BRUSSELS, July 12 (Reuters) - The European Union may make it easier for governments to slash energy tax rates if prices jump unexpectedly, under draft proposals countries are discussing to overhaul the taxes in the bloc.

The European Commission proposed a revamp of EU energy tax rules in 2021 to make them more climate-friendly, including by introducing taxes on polluting aviation fuels, which currently escape EU-wide levies.

EU countries have struggled for years to agree on the proposal. Belgium, which led negotiations in the first half of this year, eventually halted talks because of the splits between countries over issues including whether to tax shipping and jet fuels.

Hungary, which this month took over the EU's rotating presidency, has revived the policy and proposed a compromise, a document seen by Reuters showed.

One of the proposed compromises would allow governments to cut energy taxes to below EU-minimum rates, if the price of electricity or an energy product rises by more than 40% over three months, the document showed.

This would make it easier for governments to quickly cut taxes, to curb consumers' bills, in response to an energy crisis like the one Europe faced in 2022, when gas prices soared to record highs after Russia cut deliveries to Europe.

"The effect of a price increase higher than 40% has such a significant impact on the economy and households, that needs to be addressed by the member states," the draft compromise said.

Previously, the EU tax proposal would have only allowed such tax cuts if energy prices soared by 70% over six months.

But in an acknowledgement of the remaining splits, Hungary's proposal did not touch the sensitive issue of shipping and aviation fuel taxes, which the document said need to be addressed later at a "higher political level".

Some EU diplomats were sceptical an agreement on the policy could be reached. Previous rounds of negotiations have failed to win governments' backing, despite offering exemptions to island countries concerned about how aviation fuel taxes would affect their economies.

Changing EU tax policy is difficult because it requires unanimous approval from all EU countries - meaning any one government can block it.

Diplomats from EU countries will discuss the compromise on Friday. (Reporting by Kate Abnett; Editing by Emelia Sithole-Matarise)