Sinn Féin has urged the new Northern Ireland secretary, Chris Heaton-Harris, to lean on the Democratic Unionist party (DUP) to restore the power-sharing executive at Stormont. Michelle O’Neill, the party’s first minister-designate, told Heaton-Harris on Thursday that the British government should stop “pandering” to the DUP, which has paralysed power-sharing in protest against the Northern Ireland protocol. “There must be a deal. We must find a way forward,” O’Neill said after meeting Heaton-Harris on his first visit to Northern Ireland since Liz Truss, the prime minister, appointed him on Tuesday. “My focus, and I suppose my message, to the new secretary of state this morning was very clear: it’s get down to business; work with others, find an agreed way forward,” said O’Neill. “Bring that certainty and stability that is required. Get an executive up and running and stop pandering to the DUP.” Heaton-Harris was to meet the DUP leader, Jeffrey Donaldson, later on Thursday, followed by meetings with other party leaders next week. Speaking to journalists earlier on Thursday, Heaton-Harris reiterated the government’s desire to revive Stormont but did not give details. “I am looking forward to delivering enough pressure so we can get the executive up and running, solve the problems of the protocol and some of the more useful domestic things I can do to help people here in their everyday lives.” The DUP’s boycott of Stormont has been popular with grassroots unionists, who wish to see the Irish Sea border – a result of the post-Brexit protocol – removed or weakened. Critics say the executive’s paralysis has hobbled efforts to alleviate the cost of living crisis and could become politically untenable for the DUP as energy prices rise. However, Truss told the House of Commons a plan to freeze energy bills at an average of £2,500 a year for two years from 1 October would cover Northern Ireland, which has a different energy market and rules. Conor Murphy, Sinn Féin’s finance minister, said the prime minister’s promise lacked detail, leaving doubt over energy bills in Northern Ireland. “This will bring little comfort to individuals who are having to decide between heating and eating. Likewise, businesses trying to plan ahead for the winter months have no certainty as to when support will be forthcoming.” Sammy Wilson, the DUP MP, said resolving the protocol should be the government’s priority. “Until that is dealt with, people will find that their cost of living goes up even more than the rest of the UK, due to additional costs which the protocol is imposing on goods coming into Northern Ireland. The cost of living issues are not going to be dealt with by Stormont – Stormont doesn’t have the money. It is going to come from Westminster.”