Sri Lanka T20 captain Wanindu Hasaranga said his side were keening to keep up their wins against Afghanistan as they look for a short-format morale boost ahead of this year's World Cup.

The island nation sealed a comfortable win over Afghanistan inside four days before sweeping their ODI series 3-0 ahead of their first 20-over match in Dambulla starting Saturday.

"We have been unbeaten so far against Afghanistan and we want to continue the winning momentum," Hasaranga told a press conference.

"We only have six more games before the World Cup," he added. "It will be an exciting series and we are confident of finishing on top."

Afghanistan have been hampered through the tour by the absence of key bowlers Rashid Khan and Mujeeb Ur Rahman due to injuries.

But assistant coach Rais Ahmadzai said he was hopeful of bouncing back in the remaining matches.

"This is an opportunity for us," he told reporters. "Our T20 specialists are in town. We hope to finish off the tour well."

Afghanistan have been known to surprise in white-ball matches.

Ahmadzai said his team's strong representation in the Indian Premier League (IPL) left them sure to pose a formidable challenge at the T20 World Cup in June.

"We have lot of players involved in league cricket with nine of the guys involved in the IPL," he said.

"That's a lot of experience. We would like to finish top four in the World Cup and every team will worry playing Afghanistan."

The remaining T20 matches will also be played in Dambulla on Monday and Wednesday.

Sri Lanka will next head to Bangladesh in March for an all-format tour including their final three 20-over matches before the T20 World Cup in June.