Egypt’s president Abdel Fattah el-Sisi has ordered preparations to unload the giant container ship wedged in the Suez Canal if last-ditch efforts fail to dislodge it, highlighting the growing risk that the closure of the crucial trade artery could drag on for weeks.

Rescue teams were gearing up on Sunday for another effort to free the 220,000 ton Ever Given, with expectations of higher tides and signs of some limited movement in the ship’s position offering hope it can still be freed while fully loaded.

But Sisi’s first known intervention since the Taiwanese-operated vessel became stuck on Tuesday highlights fears that unloading at least some of the 40-foot containers onboard — an arduous and time-consuming task — could be the only option.

Osama Rabie, head of the Suez Canal Authority (SCA), said on Sunday it had asked international salvage company Smit, which has been assisting with rescue efforts, to start planning and sourcing equipment for the unloading.

“For this we will need and will ask for [help] and we are discussing it now so that if we get there we would not be late,” Rabie told Egyptian channel Extra News. “We should start to assemble the necessary equipment so that if we need it we do not add to delays.”

On Sunday evening Leth Agencies, a transit agent at the Suez Canal, said the SCA had decided to “postpone” the next refloating attempt until it had additional tugs deployed, probably until Monday evening when tides should be beneficial.

Bernhard Schulte Shipmanagement, the technical manager of the vessel, said a specialist tug had arrived during the day. Another tug is expected to arrive on Monday, with an additional dredger expected on Tuesday, the two companies said.

The blockage of the canal, which roughly 12 per cent of global seaborne trade passes through, has left manufacturers and retailers rushing to secure their supply chains. Around 10 per cent of global seaborne crude oil trade also relies on the canal.

The prospect of a prolonged disruption has heightened fears of shortages of components and products from car parts and commodities to toys and toilet paper. Almost $10bn of goods are being held up on either side each day, according to Lloyd’s List, a shipping data company.

Oil prices have been boosted by the closure while shipping and tanker rates have risen, as the supply of available vessels will tighten if ships need to sail the longer route around Africa.

Two high-powered dredgers worked through the night on Saturday to shift mud and sand, while two more tugboats were racing to join the 12 participating in the salvage operation on Sunday, according to Leth Agencies, a transit agent in the canal.

Rabie at the SCA said the boat had moved by about 4 metres on Saturday describing it as a “small and slow movement, but it is positive”. He also said there had been water under the ship’s rudder and propellers since Saturday, but that a 2 metre increase in the tide that evening had not been enough to free the vessel.

Shipping analysts said ships such as Ever Given typically have predominantly 40-foot containers on board with maybe a quarter being smaller 20-foot containers, all of which require specialist cranes to lift if the decision is made to start unloading. That would mean it is carrying well in excess of 10,000 containers.

There are questions over how to offload them, given the sandy banks of the canal are far from ideal for placing tens of thousands of tonnes of goods. The sheer height of the ship also poses a challenge, with containers stacked up to 60m high onboard.

Shipping companies have escalated their warnings over the seriousness of the crisis, which has become a rich source of memes and online humour.

Mediterranean Shipping Company, a Swiss-Italian shipping company, warned over the weekend that it would be “one of the biggest disruptions to global trade in recent years”. Shipping companies are diverting vessels around South Africa’s Cape of Good Hope and considering options to air freight time-sensitive goods.

Even if the Ever Given can be freed in the next few days the industry still faces weeks or even months of disruption, with ships and containers out of position and heavy congestion expected at ports in Asia and Europe once the backlog of vessels can clear the canal.

Dozens of container ships and oil tankers have already started to reroute around Africa, which will add more than a week to journey times.

The White House on Friday said the US was offering assistance to Egyptian authorities to help free the vessel, in a sign that concerns over the canal’s closure has reached the highest levels of government internationally.

“God willing we will also talk to the Americans on the issue of providing these ships in case we need to lighten the load,” Rabie of the SAC said, referring to waterborne cranes and other equipment expected to be needed to unload the containers.

Rabie said the SAC was assisting some of the more than 300 ships waiting at the north and south ends of the canal, including offering feed and veterinary assistance to those carrying livestock.

Peter Berdowski, chief executive of Boskalis, owner of Smit Salvage, which has been working to free the ship, told Dutch TV programme Nieuwsuur on Friday that he was still hopeful the ship could be freed at the start of next week “but everything will have to work out exactly right for that”.