TOKYO (Reuters) - Canada's Alimentation Couche-Tard ( ANCTF ) said on Tuesday it is confident in attaining the U.S. regulatory approvals required to buy out Japan's Seven & i Holdings ( SVNDF ) after the latter said antitrust law would be a barrier to any deal.

Couche-Tard also said it was frustrated by Seven & i's ( SVNDF ) limited engagement, although the two have begun working together on a plan to offload U.S. stores so as to gain regulatory approval.

The comments are the latest salvo in what would be Japan's largest foreign buyout in history, and contradict Seven & i's ( SVNDF ) newly appointed CEO Stephen Dacus, who has reiterated that significant regulatory hurdles stand in the way of a merger.

Seven & i ( SVNDF ) did not immediately respond to a request for comment.

The companies are the top two players in the U.S. convenience-store market, with about 20,000 locations between them.

Couche-Tard said it had identified a portfolio of U.S. stores to potentially offload and had begun talks with prospective buyers at the behest of Seven & i ( SVNDF ).

The Canadian suitor submitted a revised non-binding proposal in January, but had not been permitted to commence due diligence which would allow it to enhance its bid, Couche-Tard said.

"We have reiterated several times over the past few months that we intend to be friendly and persistent in pursuing a transaction," Couche-Tard said.

"We have done that in the face of significant frustration and distraction."

Couche-Tard, which operates the Circle-K chain of convenience stores, has a long record of acquisitions and said it planned to finance the buyout with a combination of equity and debt.

It added that it had received letters from Goldman Sachs, Royal Bank of Canada, and Scotiabank in support of its financing, which would be sized to maintain its strong investment-grade credit rating.