The Sensex was trading 74.84 points, or 0.37 per cent higher at 20,441.66 points at 1215 hours. Besides auto scrips, banking, power, healthcare and capital goods shares supported the rise.
The broad-based National Stock Exchange index Nifty also edged up 18.20 points, or 0.30 per cent, higher to trade at 6,066.55.
Brokers said the budget proposals like cut in excise duty on small cars, motorcycles, and commercial vehicles from 12 to 8 per cent and 12 to 10 per cent in capital goods sector, triggered selective buying activity.
Investors were also enthused by Finance Minister P Chidambaram saying that the fiscal deficit would be contained at 4.6 per cent of GDP in 2013-14, traders said.
The BSE auto sector index was up by 0.26 per cent at 11,998.63 as stocks of Mahindra and Mahindra, Maruti Suzuki, Hero MotoCorp and Bajaj Auto were trading with gains of up to 2 per cent.