SINGAPORE--Heineken NV (HEIA.AE) scooped up $293 million worth of Asia Pacific Breweries Ltd. (A46.SG) shares Tuesday, as the Dutch brewer moved to pre-empt any plans by Thai rivals to scuttle a possible takeover of the maker of Tiger Beer as it jostles for a stronger position in Asia's fast-growing beer market.

Heineken bought more than 6.9 million APB shares--or 2.68% of the company--at 53 Singapore dollars ($42.40) apiece via open market purchases and block trades, the world's third-largest brewer by sales said Wednesday in a regulatory filing to the Singapore Exchange. The purchases boost Heineken's direct stake in APB to 12.18% from 9.5% previously.

The purchases come after the Dutch brewer agreed this weekend to pay S$5.6 billion for Fraser & Neave Ltd.'s (F99.SG) direct and indirect stakes in APB with an improved offer of S$53 per APB share. Heineken, which originally offered S$50 per share, said that with its sweetened offer, it would now cost US$6.3 billion to buy all of APB.

F&N--a Singapore conglomerate with interests in beer, property and publishing--and Heineken share a 50-50 joint venture that owns 64.8% of APB. F&N also owns a 7.3% direct stake in APB.

Excluding F&N's stake, Heineken's direct and indirect interest in the 81-year old APB joint venture now stands at about 44.6%.

Heineken hasn't said from whom it bought the APB shares in the latest round of purchases. Two people with knowledge of the deal said earlier Singapore state-investment company Temasek Holdings Pte. Ltd. had sold its 1.4% stake to the Dutch brewer.

Tuesday's share buys allow Heineken to consolidate its position in APB amid concerns that Kindest Place Group, an entity owned by son-in-law of Thai billionaire Charoen Sirivadhanabhakdi, may try to complicate the Dutch brewer's plans to acquire one of Asia's most profitable beer businesses.

Earlier this month, Kindest Place, which owns 8.6% of APB, offered to pay S$55 a share for F&N's 7.3% direct stake in APB. That move prompted Heineken to sweeten its offer for APB over the weekend.

Even with Tuesday's moves, the fate of Heineken's APB bid still rests with F&N's shareholders, among them rival brewers like Mr. Charoen's Thai Beverage PCL (Y92.SG) and Japanese beverage giant Kirin Holdings Co. Ltd. (2503.TO).

Heineken, which has said it intends to take APB private, needs the approval of a simple majority of F&N's shareholders to seal a deal for the Singapore-based beer maker.

F&N's board said Saturday it accepted Heineken's improved offer and will recommend its shareholders do the same. The company hasn't set a date for the shareholder meeting yet.

ThaiBev, the maker of Chang beer, is F&N's single largest shareholder with a 26.4% stake, followed by Kirin with 15%, giving them significant sway over Heineken's APB bid.

A senior ThaiBev executive on Wednesday declined to comment on Heineken's latest moves, saying the company would comment only after F&N's shareholder meeting.

At stake for Heineken is a chance to boost its presence in Asia's lucrative beer market at a time when it is faces lackluster sales in its home base of Europe, where recession and government austerity measures have curbed consumer spending in recent years. Drinkers there have been turning to cheaper and less profitable brands, resulting in margin pressure.

APB has 30 breweries and 40 brands spanning 14 Asian countries. It also brews Heineken beer for some markets in the region. The company's Tiger and Bintang APB beer brands have nearly 50% of the beer market in Indonesia, Malaysia and Singapore, according to data provider Euromonitor.

--Phisanu Phromchanya in Bangkok contributed to this article.

Write to Chun Han Wong at chunhan.wong@dowjones.com and P.R. Venkat at venkat.pr@dowjones.com

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