He said: "Today's 25 Year Environment Plan is a welcome acknowledgement that we must make a generation-long commitment to saving nature".
Other environmental campaign groups were disappointed with the lack of new legislation to ensure that promises made in the 25-year plan were followed through and enforced.
Environment Secretary Michael Gove is set to unveil his plans for a "cash-for-return" plastic bottle scheme.
THE ambition behind the Government's new environmental plans is "terrific", and shows it to be "caring for God's creation" the Bishop of Salisbury, the Rt Revd Nick Holtam, has said.
Asked after her speech about calls for more urgent action, the PM said the government had already reduced plastic bag usage by nine billion and legislated to ban plastic microbeads used in cosmetics and cleaning products.
The speech comes as The Guardian reported this week that the government's Brexit Withdrawal Bill may have breached the worldwide Aarhus convention, which requires public consultation on new environmental legislation.
Marcus Glover, chief executive at WRAP said: "So far the solutions to plastic waste have been piecemeal".More news: Chelsea 0-0 Leicester: Watch highlights as hosts escape with draw
"According to the United Nations, eight million tonnes of plastic leak into oceans each year", the Waterford Senator added.
For example, the plan wants to encourage development to include green infrastructure such as sedum roofs to encourage wildlife and prevent flooding, but there was no plan to prevent development without it gaining planning permission, she said.
The 5p charge for plastic bags could be extended to cover almost all retailers as part of the government's plan to tackle our "throwaway culture".
Green campaigners were delighted to hear Theresa May highlight the need to enhance the natural environment during her historic speech at London Wetland Centre yesterday (11 January).
It extends a requirement, introduced for supermarkets in 2015, for all shops to charge 5 pence (6.5 cents) for plastic carrier bags.
Mrs May described the problem of plastic waste, much of which ends up as damaging pollution in the seas, as "one of the great environmental scourges of our time".
She said: "Today I can confirm that the United Kingdom will demonstrate global leadership". He added: "There was much to welcome. They should start by rolling out more robust and swift measures to stop plastic waste harming our oceans, clean up illegal air pollution and support the clean energy sources that can help stop climate change". A cross-government project, led by Natural England, will review and update existing standards for green infrastructure by summer 2019.
He said: "The Government has promised a Green Brexit, with the United Kingdom free to take the best from Brussels and build on this to create a world leading green economy and environment".