HONG KONG — Citing national security concerns, the Australian government on Thursday rejected competing bids from Hong Kong and mainland Chinese groups for control of a company that supplies electricity to Sydney and neighboring areas.

Key sectors of Australia’s economy, like mining and agriculture, rely heavily on Chinese demand. But local wariness toward China’s growing economic influence has risen in recent years amid a wave of Chinese takeovers of Australian businesses.

At the same time, an influx of wealthy buyers from China has helped push up real estate prices in urban centers like Sydney and Melbourne, pricing local residents out of the market.

In response, the Australian government, in accordance with its foreign investment review legislation, has been carefully vetting the sale of key assets to Chinese interests and has blocked several high-profile transactions. Officials have also ordered Chinese buyers to sell homes acquired in violation of Australia’s restrictions on foreign investment in real estate.