The world's top brewer Anheuser-Busch InBev will cut around 5,500 jobs after it completes its huge merger with rival SABMiller, a source with knowledge of the matter has told AFP.

Investor documents posted online today said the Belgium-based brewer of Budweiser and Stella Artois would slash about 3% of its enlarged staff over three years following the tie-up.

SABMiller employs about 70,000 employees in more than 80 countries, while AB Inbev has about 150,000 staff in 26 countries, according to company figures.

AB InBev is already the world's top brewer and the SABMiller acquisition is in line to be the third largest merger in history if it goes through.

A crunch vote by SABMiller shareholders to clinch the deal is set for 28 September with the companies to be officially combined on 10 October.

AB InBev last month raised its offer for SABMiller to 45p a share, after sterling slumped following Britain's Brexit vote to leave the EU, cutting the value of the deal to global investors when measured in other currencies and triggering shareholder resistance.

The new offer values the London-headquartered firm at about £79 billion (€92 billion), and the deal is expected to boost the unified firms' prospects in developing markets in Africa and China.