The Securities and Exchange Board of India on Tuesday said it was on a "high alert" after the market crash last week following exit polls predicting a hung Parliament and warned that it will swing into action to check any malpractice.

"Sebi is on a high alert...action will be taken if anything unusual is noticed," Sebi Chairman G N Bajpai said in Kolkata when asked about the recent fall in share prices.

Though the rise and fall of stock prices was a normal phenomenon in a stock market, he said Sebi will swing into action if any malpractice was detected.

• The Sebi Saga : Complete Coverage

In order to revive the regional bourses, Bajpai said Sebi will take a decision on the merger of regional stock exchanges under a common platform 'Indonext' in a couple of months.

Sebi had received a proposal to form Indonext, on the lines of Euronext, from 14 regional stock exchanges, he said.

A combined order book will help the common trading platform in increasing liquidity and determining the right price of shares listed on the regional exchanges, he said, adding
Sebi will give its recommendations and refer it to the Federation of Indian Stock Exchanges.

In a bid to attract foreign companies to tap the Indian market, Bajpai said the regulator was working on the guidelines of Indian Depositories Receipts.

Sebi also plans to introduce T+1 (transaction date plus one) rolling settlement system to impart efficiency and attract more foreign investors.