A Microsoft executive sent workers an upbeat email outlining a vision of how the software giant expects to take over Yahoo and merge the companies' cultures and resources.

Yahoo spurned Microsoft's $US44.6 billion bid for the veteran Internet firm on February 11.

Microsoft is reportedly planning a hostile takeover bid if Yahoo's board of directors does not change its mind.

In a message to employees, Microsoft platform and services division president Kevin Johnson shared "a perspective of the process going forward".

"We look forward to a constructive dialogue with Yahoo's board, management, shareholders, and employees on the value of this combination and its strategic and financial merits," he said.

"Once Yahoo and Microsoft agree on a transaction, we can begin the integration planning process in parallel with the regulatory review."

If Yahoo capitulates, the transaction would likely close in the second half of this year, Mr Johnson says.

Microsoft said it plans to keep Yahoo in Silicon Valley and hold onto engineering and business talent at the company.

- AFP