PETROCHINA'S parent company has bought 60 million of its Shanghai-listed shares after the government encouraged buybacks to boost the country's stock market.

China National Petroleum Corp increased its stake to 86.32 percent from 86.29 percent, PetroChina said in a Hong Kong stock exchange statement.

The stock is worth 728.4 million yuan (US$107 million) based on yesterday's closing price, Bloomberg News said.

China plans to ease rules for buybacks in order to help boost a stock market that had slumped 61 percent this year as of September 19.

The new regulations helped cause the CSI300 Index to jump 6.5 percent yesterday.

China National may raise its stake in PetroChina by as much as 2 percent in the next 12 months, according to the statement.

The oil company jumped 10 percent to 12.14 yuan in Shanghai yesterday. Its Hong Kong stock rose 5.1 percent to close at HK$8.67 (US$1.1).