The chair of the Business, Energy and Industrial Strategy (Beis) Select Committee has pushed Greg Clark to clarify the government's stance on controversial energy price caps ahead of a hearing this week.
Rachel Reeves has asked the business secretary to explain whether capping energy bills is the government's "unequivocal intention", the Sunday Times reported.
Greg Clark will face questions from the select committee on Wednesday as it examines the details and likely impact of the legislation. Further evidence hearings are expected to take place in December and January.
“As a committee we want to take a close eye to the government’s proposals and make recommendations to ensure that the reality of a price cap can match the rhetoric by delivering lower bills for consumers and fixing the broken energy market," Reeves said at the announcement of the call for evidence.
The Labour MP was reportedly resistant to spending time debating the proposals if they were likely to be dropped, however.
Beis earlier this month published a draft bill suggesting an absolute price cap on standard variable tariffs (SVTs) until at least 2020. Ofgem would then have the power to extend the temporary cap until the end of 2023.
The plans have been criticised over their potential to cause unintended consequences, such as pushing up bills in the longer term and making consumers even less engaged with the market.
Big Six energy suppliers in particular have come out hard against the proposals as they make a large chunk of their profits from SVTs.
Last week, a government-commissioned review by Dieter Helm, a professor at Oxford University, concluded energy bills in the UK were "significantly higher" than needed.
Helm made a number of radical recommendations to help push energy bills down, which Clark said Beis would consider.
A Beis spokesperson said: “The government is absolutely clear on the need for an energy cap. That is why we are legislating.”