(Adds details about the vote, background)
FRANKFURT, June 1 (Reuters) - Linde and Praxair said their boards voted on Thursday to approve the $73 billion merger of the two industrial gases companies despite Linde labour opposition that had threatened to torpedo the deal.
The all-share merger of equals is intended to create a market leader that will overtake France's Air Liquide, reuniting a global Linde group that was split by World War One a century ago.
Linde's chairman, Wolfgang Reitzle, did not need to use his casting vote to get the deal approved by the German company's supervisory board, four sources familiar with the matter said after a roughly 10-hour meeting.
Linde's supervisory board voted six to five in favour of the deal, the people said, with the abstention of one of the labour representatives who have an equal say with shareholder representatives on the board.
The deal must still be approved by 75 percent of Praxair investors at a shareholder meeting.
The companies raised their cost-savings target from the merger to $1.2 billion euros from $1 billion within three years - including efficiency programmes already initiated.
The new company will be incorporated in Ireland, while its principal governance activities, including board meetings, will mainly take place in Britain.
The deal is expected to close in the second half of 2018, the two companies said.
Linde and Praxair will hold a news conference at 0900 GMT on Friday in Munich. (Reporting by Georgina Prodhan and Joern Poltz; Editing by Sabine Wollrab and Edmund Blair)