Sanna Marin has insisted she works hard as Finland’s prime minister but should also be entitled to a private life, after a photograph taken at her residence of two topless women kissing sparked renewed criticism of her partying.

“I am human,” Marin told reporters on Wednesday at the conference of her Social Democratic party, describing the past week as “quite difficult”. On the verge of tears, she said she too sometimes longs “for joy, light and fun amidst the dark clouds”.

The 36-year-old, the world’s youngest head of government when she was elected in 2019, added: “I haven’t missed a single day of work. I want to believe people will look at what we do at work rather than what we do in our spare time.”

She said she had not left “a single task undone – and I won’t leave this one in the middle either. I’m learning. But I am doing my job as well as I have been up to now. I’m thinking about Ukraine, I’m thinking about you, and I’m doing my job.”

On Tuesday, Marin apologised for the photograph, which first appeared on the TikTok account of the model and influencer Sabina Särkkä. It shows her and another woman – not Marin – kissing and lifting up their tops, with a “Finland” sign over their breasts.

“I think the picture is not appropriate, I apologise for it. Such a picture should not have been taken,” Marin said. But otherwise “nothing extraordinary happened” at the party in her residence, Kesäranta, after the Ruisrock music festival on 8 July, she said.

The apology came after Marin made headlines around the world last week when video emerged of her drinking and dancing exuberantly during another private party at which unsubstantiated reports claimed drugs may have been consumed.