* Publisher fires Richard Wallace and Tina Weaver
* Moves to seven-day publishing to improve efficiency
* Shares up 3.8 percent
LONDON, May 30 (Reuters) - British media group Trinity Mirror fired the long-serving editors of its flagship daily and Sunday tabloids, saying on Wednesday it was moving to a seven-day publishing model to improve efficiency.
The company, which is also seeking a new chief executive, appointed Lloyd Embley, previously editor of its Sunday tabloid The People, to edit both titles.
CEO Sly Bailey said earlier this month she would step down at the end of the year after a shareholder revolt over pay.
"Richard Wallace and Tina Weaver will leave the company with immediate effect," Trinity Mirror said. "The decision... is a further step towards creating one of the most technologically advanced and operationally efficient newsrooms in Europe."
Trinity Mirror shares were up 3.8 percent to 27.22 pence at 1046 GMT, against a European media index down 1.3 percent.
Wallace became editor of the Daily Mirror in 2004, succeeding Piers Morgan, who was fired for publishing false images of British soldiers in Iraq.
Morgan, now host of a U.S. chat show, has been accused of showing other journalists how to hack phones - the illegal practice that brought down Rupert Murdoch's News of the World. He has denied authorising phone-hacking during his editorship.
Weaver had been editor of the Sunday Mirror since 2001.
Trinity Mirror says it has carried out a review of its editorial controls and procedures and has obtained written confirmation from its senior editorial executives that they have not engaged in phone-hacking or bribery.
Bailey is leaving after shareholders took issue with her large pay package in the midst of falling profits and sales, as the newspaper industry battles declining readership and belt-tightening by advertisers.
She received almost 1.8 million pounds ($2.8 million) last year, while the company's operating profit fell 15 percent to 104 million pounds despite cost cuts that included axing jobs and freezing salaries.