ATHENS (Reuters) - Greek Prime Minister Kyriakos Mitsotakis urged the European Commission on Tuesday to tackle power price discrepancies across the bloc, repeating previous calls for an electricity market with a more even sharing of electricity.

Greece and other countries in southeastern Europe have seen power prices rising much faster than their northern peers since the Ukraine war interrupted Russian pipeline gas supplies to Europe.

After power prices spiked in Greece last summer, Mitsotakis wrote to the European Commission demanding a solution to the "unacceptable" differences in electricity costs across Europe.

In a new letter to the European Commission, seen by Reuters, Mitsotakis said power prices remained elevated and asked Brussels to move faster against electricity cost disparities which he said violated the rule of the free flow of goods in the bloc.

Greece is building more renewables and diversifying its gas resources. But with prices pegged to the more expensive gas-fuelled power plants and without enough cross-border integration, there is sometimes too much power for one market, forcing producers to curtail supply.

"We cannot have one country with electricity prices in triple digits while, at the same hour, another country has zero or negative prices," Mitsotakis wrote in the letter.

"In electricity, we need a new push on the internal (EU) market," he added, proposing an EU task force to look at regulatory and technical solutions and new investments to help boost cross-border power flows in the 27-nation bloc.

The EU has estimated that it would need to spend 584 billion euros in upgrading its power grids this decade to ensure grids can carry larger amounts of green energy.

With regard to power grids, the EU should review its long-term planning to take into account available resources and technologies in each country and include compensation for those whose investments offered outsized benefits, Mitsotakis said.

(Reporting by Angeliki Koutantou and Renee Maltezou; editing by Mark Heinrich)