The rise was on the back of buying mainly in Consumer Durable, Realty and Banking sectors in view of firm Asian cues even as the Metal sector witnessed selling.
The sensex resumed higher at 20,438.87 and firmed up further to 20,481.76 on initial strong buying. However, it declined afterwards to 20,392.44 before quoting at 20,403.98 at 1030 hrs, still showing a gain of 37.16 points or 0.18 per cent from the its last weekend's level.
The NSE Nifty also moved up by 7.50 points or 0.12 per cent to 6,055.85 at 1030hrs. Major gainers were Tata Power 2.64 pct, Dr Reddys Laboratories 1.82 pct, Axis Bank 0.99 pct, HDFC Bank 0.90 pct and * Oil & Natural Gas Corpn 0.87 pct.
Asian stocks rose in early trade after China's new credit figure showed a record increase in January, boosting optimism the world's second-largest economy can maintain its growth momentum.
Key benchmark indices in China, Hong Kong, South Korea, Indonesia, Taiwan, Japan and Singapore rose by 0.16 pct to 0.84 pct.
US stocks rose on last Friday as investors shrugged off a report showing poor industrial output last month as mainly weather-related.