By Freya Berry

LONDON (Reuters) - SABMiller's <SAB.L> board will review its $107 billion merger deal with Anheuser Busch InBev <ABI.BR> once all regulatory approvals have been secured, its chairman said on Thursday.

The two companies received approval on Wednesday from U.S. antitrust regulators, after they agreed to sell assets and preserve competition from independent craft brewers. The companies are now waiting for China's approval.

However, the drop in sterling since the UK voted to leave the European Union has reduced the relative appeal of the all-cash offer aimed at most of SAB's shareholders.

Shareholders also voiced concerns about a stock-and-cash alternative structure, created as part of the takeover and designed for SAB's biggest investors, cigarette maker Altria <MO.N> and Colombia's Santo Domingo family.

At the company's annual general meeting (AGM) on Thursday, Chairman Jan du Plessis said the board would consider AB InBev's offer after it had received preconditions from Chinese regulators.

The board would also take into account sterling's fall. "We continue to listen to shareholders," du Plessis said, when asked at the meeting if he would reconsider the terms of AB InBev's offer in light of the changed market environment.

"The board will take into consideration all relevant facts and circumstances that we think should be considered."

The firm would then write to shareholders, he said. A spokesman for SABMiller declined to elaborate further.

A source familiar with the matter told Reuters on Wednesday that the company's board was weighing the terms of AB InBev's offer, amid rising shareholder disquiet.

Du Plessis described the pending takeover by AB InBev as a "significant distraction", but said the deal was right for the company and its shareholders. Australia, Europe and South Africa have already cleared the deal, which is expected to close by the end of the year.

The maker of beers such as Castle Lager, Peroni and Grolsch earlier reported group net revenue fell 4 percent in its first quarter, ended June 30, with volume flat.

Du Plessis defended the deal's partial share alternative (PSA) structure, saying it had been vital for securing approval of the takeover from the two major shareholders.

In response to a shareholder question, he said he would "make a point" of asking AB InBev to issue shares as part of a share swap, in order for SABMiller shareholders to have a holding in the newly merged company.

(Reporting by Freya Berry; editing by Susan Thomas and Ruth Pitchford)