Business secretary Sajid Javid has faced calls to quit after it emerged he took his daughter on a trip to Australia while the UK steel industry was in crisis.
The cabinet minister cut short his visit to Sydney to return to Britain following the shock decision by Indian-owned Tata to sell its UK assets.
This could leave the giant steelworks in Port Talbot facing closure if it doesn't find a buyer and put thousands of jobs at risk.
The plant's local MP and unions were furious that Mr Javid appeared to have gone on the trip not for "entirely work-related" reasons.
Labour MP Stephen Kinnock, whose Aberavon seat includes the Port Talbot plant, said Mr Javid should consider quitting.
He told ITV News: "For him to have not been in engaged in entirely work-related activities, I think, compounds that error of judgment.
"And I have therefore suggested he considers he position."
A spokesman for the Unite union said: "Everybody needs a holiday and time with their family.
"But with alarm bells ringing in the steel industry it is remarkable and does pose questions as to how alert the Secretary of State was to the latest crisis facing the industry."
Prime Minister David Cameron has said the government is "doing everything it can" to secure the future of steel making in Port Talbot but that "nationalisation is not the answer".
A senior source close to Javid said it was "insulting" to suggest he was not focused on the steel industry's future.
They added: "The fact he has just spent almost 24 hours in the air, flying half-way across the globe, proves how seriously he takes what is going on at Port Talbot."