Greece may be able to indefinitely avoid gas supply problems, even if Russia halts flows of the fuel, Energy Minister Kostas Skrekas said, adding that his country's next payment to Russian supplier Gazprom was due this month.

The measures will secure supply without any time limit if sufficient gas is available on the world market, Skrekas told Greek Skai television.

On Thursday, Russian President Vladimir Putin said he had signed a decree requiring foreign buyers to pay in roubles for Russian gas from April 1. Contracts would be halted if the payments were not made.

The order has sparked concern over gas supplies across Europe.

"The next payment is around April 20, but we can't wait until then to see what will happen," Skrekas said.

Under its contingency plan, Greece, which uses gas mainly for power generation, would get additional quantities of liquefied gas and switch four gas-fired electricity plants to diesel, he said. It might also ramp up Azeri gas purchases.

Spare coal-fired generating capacity can also be activated.

"With all these, and if there are available gas quantities in world markets, ... there will be no time limit in terms of security of supplies," he said.

(Reporting by Angeliki Koutantou; Editing by Bradley Perrett)