The 36-year-old made the admission ahead of the Boxing Day Test against Australia in what he admits could be his last tour with Sri Lanka in the longest format.
"I spoke to my managers and my family about how far I want to play Test cricket and one-dayers," said Dilshan, who blasted a superb 147 in the opening Test defeat in Hobart last week. "I'm definitely going to play in the 2015 World Cup, that's my target but I'm not sure how long I'm going to play Test cricket."
He added: "After this series, I'll sit down with my wife and family and discuss when I'm going to finish Test cricket - (the Test in Sydney) might be my last outside of Sri Lanka."
Dilshan, who has 83 caps, quashed talk of a potential return to Test cricket for paceman Lasith Malinga, who has spent time with the team's bowlers ahead of Wednesday's MCG clash.
Malinga retired from the Test arena in 2010, electing to focus on one-day and Twenty20 cricket and he has flourished for the Melbourne Stars in the Big Bash League this season - leading the bowling charts with eight wickets.
His form has sparked calls for a return ahead of the third and final Test in Sydney, but Dilshan played down such suggestions.
"I don't think he is coming back to Test cricket," he said.
"He wants to concentrate on one-day international and Twenty20 cricket. He wants to be 100% in the shorter form of the game and that's why he made the decision to stop Test cricket.
"If he comes back, it would be good for the side. Everyone would be happy to see him back but I don't think he will change his mind."