The All Share Price Index rose 0.55 percent (11.76 points) to end at 2,154.22 while the more liquid Milanka went up 0.
52 percent (12.77 points) to close at 2,457.05, according to provisional stock exchange figures.
Turnover was 985 million rupees.
Chinthana Hatangala of Lanka Securities said positive sentiment prevailed throughout the day.
"Like last week, we're seeing healthy turnover levels from most counters," he said.
"Especially during the last three days we've seen high interest on hotels, and prices also appreciated."
Dialog Telekom was the highest contributor to the day's turnover with a number of crossings or off-the floor-deals.
Dialog Telekom was the most active in terms of volumes with over 46 million shares changing hands. It closed flat at 5.50 rupees.
The firm's share price has been stagnant as it is making heavy losses.
Hatangala said the blue chips, hotels and banks were the "most popular picks".
He said turnover levels had been around a billion rupees a day from last Monday when news broke that the war had ended.
This week too turnover levels had been hovering just below a billion rupees a day.
"From last Monday we've seen active participation by both retailers, corporate and high net worth indiviuals," Hatangala said.
"Because of the positive news we can expect the trend to continue, even though in the overall market there may be fluctuaions with profit taking.
"But stocks with fundamental value and high earnings potential will move up.
"