UPDATE 1-Australia's ASX says must join global bourse consolidation

* Deals faces political opposition in Australia

* Shares edge higher following losses earlier in week

* Australia's FIRB may take 120 days to consider deal (Adds detail, background)

SYDNEY, March 24 (Reuters) - Australian bourse operator ASX says it continues to believe in the business logic of a proposed $7.6 billion takeover by Singapore rival SGX and also saw a need to take part in global bourse consolidation.

"The ASX Board maintains a strong belief in the need to participate in global exchange consolidation and in the business logic of the announced combination with Singapore," it said in a statement on Thursday.

"The recent merger announcements by the London and Toronto exchanges as well as by NYSE Euronext and Deutsche Borse, underscore the dynamic forces driving developments among global exchanges."

The ASX made the comments in a letter to shareholders released Thursday as it ramps up lobbying efforts to try and overcome political opposition to the deal which comes amid a wave of bourse consolidation globally.

ASX shares, which fell earlier this week on media reports that the government was set to reject the merger, edged up 0.3 percent to A$34.63 in early trade.

The deal is currently under review by the Foreign Investment Review Board (FIRB) which has up to 120 days to make a decision.

The reports could add pressure on the Singapore Exchange to further sweeten the terms of the deal, even though SGX CEO Magnus Bocker has said there will be no more concessions.

SGX's bid for ASX, first announced in October, has already been under pressure from Australian politicians -- whose approval is necessary to lift a 15 percent shareholder cap -- as it was seen as ceding control over a key national institution and a de-facto monopoly.

The deal faces several key hurdles: first it needs approval from the Treasurer after the FIRB comes up with a recommendation, then parliament has to agree to lifting a 15 percent shareholder cap in ASX, and finally, it needs approval from ASX and SGX shareholders. (Reporting by Michael Smith and Balazs Koranyi; Editing by Ed Davies)