Ofgem chief executive Andrew Wright said the reforms on fixed term deals will make the energy market "simpler, clear and fairer" and make it easier for consumers to "vote with their feet".
Mr Wright said in a statement:
In an era of rising prices it is vital that competition works as effectively as possible.
Our reforms seek to give consumers the tools they need to find the best energy deal for them and to ensure that suppliers have to treat them fairly.
Now we are looking for energy suppliers to pick up the baton and put their efforts into restoring consumer trust.
More top news
The former head of the Diplomatic Service breaks down the hidden meanings behind Theresa May's letter to Donald Tusk
The storms that struck Texas and Oklahoma late on Tuesday brought tornadoes, tennis ball-sized hail and powerful winds.
Samantha Baldwin, 42, and her sons Louis Madge, nine, and Dylan Madge, six, haven't been seen for two days.