The UK faces higher prices for food and fuel for at least eight months after the war in Iran ends, a minister has said.

The closure of the strait of Hormuz, a key shipping lane that carries a fifth of global oil and gas, has sent oil prices soaring since the US and Israeli attacks on Iran began in February.

Darren Jones, the chief secretary to the prime minister, said the conflict would probably continue to raise prices for energy, food and flights in the coming months as potential issues around energy supplies affect production, rather than lead to shortages on supermarket shelves.

The UK government has urged motorists to fill up their cars as usual amid higher prices at the pumps and for air travellers not to change their plans over potential jet fuel shortages.

Jones told the BBC’s Sunday with Laura Kuenssberg programme: “You’re going to see prices go up a bit as a consequence of what Donald Trump has done in the Middle East.

“That’s probably going to come online not just in the next few weeks, but the next few months. There’s going to be a long tail from this.”

Asked how long higher prices might remain, Jones suggested it would be around eight months after the strait of Hormuz was unblocked and a de-escalation of the conflict had taken place.

“I think our best guess is eight-plus months from the point of resolution that you’ll see economic impacts coming through the system,” he said.

Donald Trump announced an indefinite extension of the US ceasefire with Iran last week that paused most of the fighting, but further efforts towards ending the conflict have been unsuccessful after the US president told his envoys not to travel to Pakistan for talks at the weekend.

The UK government is stepping up planning for how to offset the impact, focusing on the live monitoring of stock levels and what plans are in place for addressing supply chain disruption.

Jones said: “The government here in the UK, the work that I’m doing with the prime minister is looking at all of those things and saying, ‘What can we do within our power to help people to get through those difficult times?’”

The government is also looking to secure stocks of carbon dioxide, which is used in the food industry and by breweries to make drinks fizzy, as well as for defence purposes and medical uses such as MRI scanning.

Jones said he was seeking to ensure there was an adequate supply of beer for fans watching the men’s football World Cup, which starts on 11 June.

He said: “I raised this issue because if there is a problem with jet fuel on holidays and carbon dioxide on beer, the summer might be pretty depressing for people, but we’re doing everything we can to make sure that it’s not the case.”

The Liberal Democrats have called for a bill to be included in the next king’s speech in May to put food security at the top of the government’s agenda.