Arkelsten was a member of parliament when she attended the gathering, which took place two years ago and brought together several environmental policymakers in the southern French city of Pau.
In a statement on the Moderate Party’s website, Arkelsten defended the trip as something which fell within her area of responsibility.
“I carried out the study trip in my then capacity as a member of the Riksdag and active in environment and climate issues,” she wrote.
A public prosecutor has announced plans to launch a preliminary investigation into the matter.
Prime minister Fredrik Reinfledt, who appointed Arkelsten to her new post earlier this month, supported his new party secretary’s view of the trip.
“She has said that she viewed it as in line with her role as a member of the Riksdag, but she has also said that it’s regrettable that it could be construed as inappropriate in some way, and I think it’s good that she’s acknowledged that,” Reinfeldt told the TT news agency.
He added that he welcomes a review of the case by a public prosecutor.
Shell arranged the PR-junket in the city of Pau, near the Spanish border. At the time, Arkelsten was environmental policy spokesperson.
Several months later Arkelsten spoke, according to the Expressen daily, favourably of Shell in the Riksdag. Arkelsten has insisted that the visit was a study trip.
Shell had organised a competition for university students challenging them to come up with the most fuel-efficient car.
“This was a study trip which was organised by Shell. It was a seminar and one could look at the cars and meet the students,” Arkelsten said to Expressen.
Malmö prosecutor, Björn Ericsson, has previously examined suspected corruption in connection with a trip arranged by Shell but found no case to answer. In 2007 three members of parliament accepted a trip along the lines of Arkelsten’s. Ericsson in March confirmed that the investigation would be closed.
Sofia Arkelsten has been criticised by several political heavyweights from the opposition parties. The Social Democrat party secretary Ibrahim Baylan argued that Shell does not pay for these types of trips without expecting to receive something in return and asked for clarification over who it is that Arkelsten in fact represents.
The Green Party’s Gustaf Fridolin has called Arkelsten’s actions “incredibly poor judgement”.
Sofia Arkelsten has meanwhile cancelled a planned blog and Twitter meeting scheduled for Wednesday, with the event put back until November.
News agency TT made attempts to contact Sofia Arkelsten on Wednesday but has not been able to reach her for a comment.