Investors can expect the "best" returns from Asian stocks in the first half of 2019 as negative sentiment from last year subsides, a J.P. Morgan strategist said.

"We're expecting more upside in the first half ... I think the best part of the returns you'll have in Asian equities will be in the first half," Mixo Das, Asia equity strategist at J.P. Morgan, told.

"At we get more clarity on the U.S.-China trade deal, China's growth bottoming out at some time in [the first] half, and the U.S. economy averting a recession in 2019 — all these things essentially will reinforce that risks are coming down and that's why equities are going to be going higher in the first half," he added.

But growth in company earnings could weaken in the second half of the year, partly due to disruptions on the trade front, which has started to hit economic activity worldwide, said Das.