The Japanese owner of 7-Eleven is considering going private by buying back its own shares in a bid to avoid a takeover by Canadian rival Couche-Tard, reports said on Wednesday.

Seven & i Holdings is eyeing the move as a countermeasure to Circle K owner Alimentation Couche-Tard's seven trillion yen ($45 billion) takeover proposal, the Nikkei business daily said.

The takeover, if realised, would be the biggest ever foreign buyout of a Japanese firm.

With around 85,000 outlets worldwide, 7-Eleven is the world's biggest convenience store chain.

Around a quarter of those are in Japan, where the stores are a cherished one-stop shop for everything from rice balls to concert tickets.

Bloomberg News also reported Wednesday that Seven & i was considering a management buyout, or MBO, worth up to nine trillion yen -- above its market cap of 5.7 trillion yen.

A Seven & i spokesman told AFP there was "nothing for public release at this point".

The 7-Eleven franchise began in the United States, but it has been wholly owned by Seven & i since 2005.

Meanwhile, Couche-Tard, which began with one store in Canada's city of Laval in 1980, now runs nearly 17,000 convenience store outlets worldwide.

The Nikkei, citing sources close to Seven & i, said the company had begun talks with financial institutions to procure the necessary resources to buy its own shares.

But it said potential obstacles could include whether the banks would agree to the huge loans required, and also whether Seven & i's founding family would support the plan.

In September, Seven & i rejected an initial takeover offer from Couche-Tard, saying it "grossly" undervalued its business and could face regulatory hurdles.

Then the group said last month it had received a revised offer that reportedly totalled around seven trillion yen.

To boost its share price and fend off Couche-Tard, Seven & i has also announced a major restructuring, including plans to spin off its non-core businesses.

To allow it to focus on 7-Eleven, its new holding company will comprise its supermarket food business, speciality stores and other businesses.