Swiss cement maker Holcim (HOLN.VX) is considering offering its shareholders a sweetener to win their approval for a planned merger with France's Lafarge (LAFP.PA), a Swiss newspaper reported on Sunday without citing a source.

The deal, set to create the world's biggest cement maker with $44 billion in sales, was agreed nearly ten months ago but since then analysts have flagged a potential divergence between the two firms' earnings outlooks as raising the possibility of a renegotiation of terms.

Swiss weekly Sonntagszeitung reported that Holcim was looking at several "creative methods" to sway its shareholders into backing the deal, including a generous special dividend or a share buyback, instead of trying to alter the terms of the deal, which involves a one-to-one share swap.

A spokesman for Holcim declined to comment on Sunday.

But Chief Executive Bernard Fontana, when asked on Monday whether the Swiss firm's strong results could affect the exchange ratio, said the merger agreement did not contain any mechanisms by which the terms could be automatically adjusted.

Sonntagszeitung reported that Holcim was considering the sweetener in response to opposition from its shareholders to the deal, which hinges on investor approval for a capital increase for financing.