President and CEO of Siemens AG Joe Kaeser (R) and Mitsubishi Heavy Industries CEO Shunichi Miyanaga attend a news conference after a meeting with the French government in Paris, on 17 June, 2014.Reuters

Siemens and Japan's Mitsubishi Heavy Industries (MHI), who together challenged GE's near $17bn offer for French firm Alstom's energy assets, have been urged to improve their offer - and appear unimpressed by the suggestion.

The French government wants rival bidders Siemens and General Electric to come up with better offers for Alstom's energy division, and expects improved offers ahead of the 23 June deadline imposed by GE for its bid, Reuters reported.

However, Siemens chief executive Joe Kaeser, describing the Siemens-MHI offer at a news conference in Paris on 17 June, said he saw no reason to discuss improving their offer.

"Why would a superior offer be improved if it is superior already? There is no reason for us to discuss that question at this time," Kaeser said.

"The talks between the state and the different companies are going to continue this week," an unnamed source in Hollande's office told Reuters.

The Siemens-Mitsubishi bid values Alstom's power business at €14.2bn ($19.3bn, £11.3bn), beating GE's existing €12.4bn offer.

The German-Japanese offer, outlined on 16 June, is complicated and analysts have said that it will break up Alstom.