Michael Gove is under pressure to use the government's aid budget to help clean up pollution.
The Prime Minister today launches a 25-year plan to improve the environment and remove all avoidable plastic waste by 2042. In a speech later today Theresa May will say people will be 'shocked' at how much plastic is wasted.
However the plan is being criticised by charities and green groups who say the promises are not binding and can be abandoned whenever they become inconvenient.
Christian charity Tearfund said the government has 'woken up to the world's waste crisis' but urged the UK to 'lead the way' by giving some of its overseas aid budget to fighting waste.
Joanne Green said the government could turn a 'crisis into an opportunity' by helping developing nations develop sustainable economies.
'Beyond cleaning up the oceans and improving health, waste can also generate jobs and improve incomes for poor people,' she said.
'If all governments allocated just 3 per cent of their aid budget to tackling the waste crisis, waste collection could be extended to the one in four people who currently lack it.'
Theresa May's proposals include plastic free aisles in supermarkets to allow shoppers to buy fruit and vegetables that are not packaged with plastic and extending the 5p charge on plastic bags to smaller shops.
'Today I can confirm that the UK will demonstrate global leadership. We must reduce the demand for plastic, reduce the number of plastics in circulation and improve our recycling rates,' she will say in extracts released before the speech.
But Friends of the Earth chief executive, Craig Bennett, said the government's previous record on the environment made him sceptical.
'It's easy to make lots of commitments about things that will be done when you're no longer in office,' he said, according to the Guardian. 'And the point is, if you look at the government's performance on some key issues over the last year, there's some real reasons to be concerned.'
The Labour party branded the speech a 'cynical attempt at rebranding the Tories' image' while the Liberal Democrats said it 'beggared belief' that a target of 2042 had been set for removing plastic waste and that action was needed now.