A multinational company run by a major Conservative donor has refused to pay a consultant it hired to advise on a potential contract in Saudi Arabia after the Serious Fraud Office launched an investigation into its activities, according to court documents.

The oil and gas services company Petrofac, headed by Ayman Asfari, had received an invoice from Urbania International Management Consultancy for 71m UAE dirhams (£14m).

However, in court papers filed in Jersey, Urbania alleged that Petrofac refused to settle its bill after the SFO launched the investigation into the oil company’s activities, arguing it would not be “appropriate” to make the payment.

Asfari has donated almost £700,000 to the Conservatives since 2009 and is a member of the Leader’s Group, an elite circle of donors who are invited to private lunches with the party’s leaders in exchange for donating £50,000 a year. Asfari’s wife, Sawsan, has also donated at least £100,000 over the past three years, according to the Electoral Commission.

He is also one of the prime minister’s business ambassadors, holding meetings on behalf of the British government while travelling overseas.

The SFO has been investigating allegations of large-scale bribery in the oil and gas industry for two years. In May last year, Petrofac announced that Asfari and its chief operating officer, Marwan Chedid, had been arrested by the SFO and questioned under caution. Its shares fell by more than £630m after the announcement.

Both were subsequently released without charge. Asfari, Petrofac’s chief executive, remained in post but was excluded from all matters relating to the SFO investigation, while Chedid was suspended. Chedid has since left the position.

According to documents filed with the royal court of Jersey, a services agreement stipulated that if Petrofac won a contract to supply work to the Fadhili gas programme in Saudi Arabia, Urbania would receive 1.25% of the contract’s value as a fee for its services.

The services included helping to develop a winning proposal to secure the tender and providing advice on regional requirements, market conditions and laws, according to the judgment of the Jersey court.

Following the award of the contract to Petrofac, Urbania submitted an invoice for its work. On 10 May 2017, Paolo Bonucci, the group head of business development at Petrofac, told Amer Samhoun of Urbania the company had “already started processing it”. Two days later, the SFO announced its investigation into Petrofac.

In August, Petrofac’s legal advisers, Freshfields, sent Urbania’s representatives a letter stating that the invoice would not be paid.

“In light of the SFO’s investigation extending to Petrofac’s agents, it is not considered appropriate, at this point in time, for Petrofac to authorise payments of Urbania’s outstanding invoice,” they wrote.

Four days later, Urbania started legal proceedings against Petrofac, which argued that court proceedings should be stayed and the dispute resolved by arbitration instead. The royal court sided with Urbania and declined to stay the proceedings.

Petrofac said: “This court decision related to a dispute on a point of Jersey law between ourselves and a provider of technical support services with whom we no longer have a relationship. We were disappointed by the outcome but respect the royal court of Jersey’s decision.”

Urbania’s lawyers said the company “has no knowledge as to why Petrofac failed to make payment on time” and said there was no suggestion of any wrongdoing by its client.

The SFO’s investigation into Petrofac was launched as a result of a separate bribery and corruption investigation into the Monaco-based oil and gas services company Unaoil, which has denied any wrongdoing. Urbania has no connection to Unaoil, according to the Jersey judgment.