"I told [the G20 finance chiefs] that it is necessary for each country to ramp up efforts [to deal with terrorist financial activities]," Aso was quoted as saying by the agency.
The finance minister's request follows several videos released by the Islamic State (IS) extremist group depicting the killing of hostages, including two Japanese nationals.
After releasing the beheading videos of security expert Haruna Yuakawa and freelance journalist Kenji Goto late January, the IS publicized a video of captured Jordanian pilot Muath Kasaesbeh being burned alive last Tuesday.
In 2013, G20 leaders issued a declaration on the need to tackle money laundering and terrorism financing.
The two-day G20 ministerial-level and central bank governors summit kicked off Monday in Istanbul.
According to various expert estimates, IS uses money made from racketeering, oil smuggling and ransoms for hostages, among other sources, to fund its operations and governance of the self-proclaimed caliphate in Syria and Iraq.
