The family and friends of a Scottish man who went missing during his brother’s stag do in Hamburg are growing increasingly concerned for his safety.

Liam Colgan, 29, from Inverness, has not been seen since about 1.30am on Saturday when he was out celebrating in advance of his brother Eamonn’s wedding, for which he is to be best man.

Speaking to the radio station LBC, Eamonn Colgan said it was “extremely out of character” for his brother to disappear and not make contact. “He’s not someone who’ll disappear to party, only to reappear days later. It’s just not something he would do,” he said.

Alan Pearson, one of 18 friends on the trip, told the BBC that Liam Colgan had separated from the group towards the end of the night. “Nobody realised at the time, given the nature of the event. It was hard to keep tabs on everyone,” he said. “Having retraced our steps and spoken to bar staff in the last bar he was seen in, we understand that he left a few minutes before the rest of the group.”

Pearson added: “When he didn’t turn up for activities he had planned on Saturday afternoon, we knew something was amiss.”

The group had spent Friday night visiting a brewery and bars in the city. Colgan was last seen wearing a brown leather jacket and a grey hoodie in the Hamborger Veermaster bar in the Reeperbahn area. He is 6ft (183cm) tall with red hair.

Eamonn Colgan said the family had put up posters in the area where his brother disappeared. He said he had been booked on to a flight home on Monday evening but had no plans to leave.

“We’re just taking it day by day at the moment, waiting to hear what we’re hoping is positive news,” he said. “My message to anyone would be that if they’ve seen him to contact me and the police. I don’t believe Liam to be missing willingly. I just hope that he’s OK.”

A post on a Facebook page set up to help find the 29-year-old read: “Liam is the best man for his brother Eamonn Colgan and is responsible for organising the stag do to Hamburg, Germany. Eamonn is due to marry his fiancee, Susan, in three weeks’ time back in Scotland so we are launching an urgent appeal to find Liam.”

A spokesman for the UK Foreign Office said: “We are in contact with the German police after a British man was reported missing in Hamburg, Germany. We are providing advice and assistance to his family.”