Japanese policymakers on Monday pledged to work closely to guard against financial market volatility after Greek voters rejected eurozone austerity measures.

"The direct economic and financial relations between Japan and Greece are limited. But government and Bank of Japan officials have held discussions early this morning" to ensure Japan responds smoothly to any market response as needed, BOJ Gov. Haruhiko Kuroda said in a statement.

Finance Minister Taro Aso also said that while Japan was in close contact with overseas policymakers on the Greek referendum, it was confident that Europeans have sufficient safeguards in place to respond to market disruptions.

"I understand that European countries ... are calling on the Greek government to act responsibly" in the wake of the referendum results, Aso said in a statement.

The yen rose against the dollar and euro in early trade after Greece voters rejected European bailout terms by a wider margin than expected.

Japanese financial institutions have very limited exposure to Greek debt, while Japan's direct trade with Greece is also minimal.

Both Kuroda and Aso did not mention how Tokyo may respond if developments in Greece jolt markets. But the central bank's first line of defense would be to inject massive liquidity to calm markets, sources have told Reuters.