Greece's debt management agency says it will start monthly sales of short-term debt in September, replacing the current quarterly sales, as it gains confidence in its ability to raise cash.

The agency said Tuesday it will be selling 13-week treasury bills, together with either 26- or 52-week bills, or both.

The move shows debt-ridden Greece is increasingly able to tap markets for funds after an international bailout spared it from defaulting in May.

In return, Greece implemented harsh austerity measures.

Passing an important market test last month, Greece raised 1.95 billion euros ($2.47 billion) through 13-week Treasury bills. The sale was oversubscribed 3.85 times at a yield of 4.05 percent.

Greece hopes to start issuing long-term debt again in 2011.