(ShareCast News) - Sports Direct said it would pay its directly employed staff and casual workers above the National Minimum Wage from 1 January 2016.The company, which has been under fire over a recent newspaper investigation over the way it treats staff at its main warehouse, said the pay rise would cost £10m a year on an annualised basis. It did not say how much it would increase workers' wages above the current rate of £6.70.Chief executive Mike Ashley revealed the move in an interview with the Daily Mirror newspaper."I realise this is ambitious and it won't be easy, but I believe as a FTSE 100 or even 250 company we have a responsibility to set a high moral standard," he said"We're putting our money where our mouth is and have notified the City we will be spending £10m ensuring all employees are above the minimum wage."He added that thousands of Sports Direct staff received "life-changing" bonuses each year.However, thousands more on zero-hours contracts are not included in the bonus scheme, an issue which is the subject of legal action.