At 12.20pm, the key index was up 9.14 points to 1,693.72.
Trading activity was robust with 6.74 billion shares crossing for RM3.96bil.
"Market players are likely to focus on banking, gaming, shipping, plantation and O&G sectors.
"Beside the construction sector is likely to be on traders' radar as news on KL-SG HSR surfaced in the media over the weekend, which may lift the trading sentiment on construction and building material segments this week," said Malacca Securities Research.
Given the overbought condition of the FBM KLCI, it may take a breather around the resistance at 1,700, it added.
Support for the index is spotted at 1,640 and 1,620.
Banking stocks led gains on onday with Public Bank maintaining strong momentum to rise 66 sen to RM22.56 on the back of a proposed bonus issue.
Hong Leong Bank rose 62 sen to RM19.62 and Maybank added six sen to RM8.97.
Tenaga Nasional was also up 44 sen to RM10.78.
The recovery theme also proved detrimental to glove stocks, which fell in anticipation of falling demand moving forwards.
Top Glove dropped 48 sen to RM6.42 and Hartalega shed RM1.46 to RM12.26.
Top active counters were Hua-An up 3.5 sne to 16.5 sen, AirAsia X climbing two sen to 11 sen and Iris rising 0.5 sen to 39.5 sen.
News of the Pfizer vaccine being shipped out as at yesterday evening lent a boost to global equities.
Asia's major markets rose with Japan's Nikkei picking up 0.5% and Shanghai's composite index adding 0.4%.
Hong Kong's Hang Seng and South Korea's Kospi were flattish while Australia's ASX 200 climbed 0.5%.