The Australian government has said it plans to reject a bid for the country's bourse on national interest grounds.
Last month, SGX, the Singapore stock exchange made a $8.3bn (£5.1bn) bid for ASX, the firm that owns the Australian Stock Exchange.
But the Australian Treasurer, Wayne Swan, has signalled he will block the deal due to "serious concerns about the proposal".
The two bourses saw the move as a way to cut costs.
The cross-border proposal has faced significant opposition in the Australian Parliament, which would have needed to approve the deal.
"Governments are getting pretty tough on lots of things," said Jason Bedow, chief executive at Argo Investments.
"I wouldn't say governments are particularly business-friendly at the moment."
The takeover blow may not rule out the Singapore bourse working closer with its Australian counterpart in future.
"We will continue to pursue organic as well as other strategic growth opportunities, including further dialogue with ASX on other forms of cooperation," said SGX in a statement.
In recent months there has been a flurry of global stock exchange takeover bids, which are seen as a way to pool resources and benefit from economies of scale.
Last week, the US exchanges Nasdaq and ICE mounted a $11.3bn bid for NYSE Euronext, to top a previous offer from Deutsche Boerse.
While in February, the London Stock Exchange (LSE) agreed a merger with TMX Group, which operates the Toronto Stock Exchange.