Criticising the current rules for hospitality businesses in level two and one as “unworkable”, the Scottish Hospitality Group warned staff could be put at risk and police time wasted due to the restrictions.
In level two, which covers much of the Central Belt, including Edinburgh and Glasgow, pubs can open and serve alcohol until 10:30pm, with areas in level allowed to open until 11pm.
During the upcoming European Championships, matches can kick off as late as 8pm.
The possibility of extra time and penalties could see landlords forced to kick out customers with games still ongoing, with the potential for confrontation sparking the warnings.
Stephen Montgomery, spokesperson for the Scottish Hospitality Group, said: “We saw in the Europa League final that the game went on to extra time and then 22 penalties.
"If the Scottish Government doesn’t give some flexibility to the current rules, we could end up in a situation where people can watch the group stages, but when it comes to the knockout round, hospitality staff are going to be forced to ask fans to leave right in the middle of all that.
“I’d like to see the officials and ministers who came up with these rules try to enforce them. Hospitality staff have taken enough punishment over the last year and they should not be forced to then ruin someone’s evening and potentially face a backlash.
"And you can easily see how trouble could start on the streets, meaning the police get called, which is a complete waste of their time.”
Mr Montgomery has led calls for the planned fan zone in Glasgow for the Euros to be cancelled due to its potential impact on nearby hospitality businesses and on Covid-19 transmission.
He said it was preferable for the public to enjoy the Euros in a “safe well-run pub” and called on the Scottish Government to “tweak the rules”.
Mr Montgomery said: “All that needs to happen is to tweak the rules so that people can finish their drink and watch the end of the game. It’s as simple as that – and it should be up to local authorities to decide what time pubs and restaurants in their patch close.
“Everyone deserves a bit of fun and relaxation after what we’ve been through, especially since it’s Scotland’s first major tournament in a generation.
"[It’s] much better to do that in a safe well-run pub with lots of public health measures, than have people in uncontrolled gatherings at home or the large, mass gatherings we saw across Glasgow last month.”
A Scottish Government spokesperson said: “We remain in a precarious position with the Delta variant causing additional levels of concern and we do not want to undermine the hard work and sacrifices that have been made to get us to this point.
“We fully understand the challenges facing the hospitality sector as we look to balance measures to suppress the virus and protect lives with keeping businesses open and trading viably.”
The spokesperson added: “We are keeping all measures relating to the Euros under review.”.”