Leicester's mayor Sir Peter Soulsby has accused his political rivals of "talking down" the city and "slagging off" some of its newest features.
He spoke out as they criticised multi-million pound projects he has led.
The mayor reacted angrily in a meeting on Tuesday when opposition Liberal Democrat city councillor Nigel Porter suggested the city's new Richard III visitor centre "isn't attracting very many visitors".
Tory member Ross Grant then criticised the delays in the completion of the mayor's controversial flagship £4 million Jubilee Square project.
Sir Peter responded, saying: "It seems to be the evening for opposition members to slag off the city's assets.
"Has Councillor Porter been bothered to go and have a look for himself before he started slagging it (the Richard III centre) off?"
Aware Coun Porter had not visited, Sir Peter said: "It's feeble for someone who hasn't been bothered to walk a few hundred yards around the corner to see it for himself."
After the meeting, Sir Peter said he had been frustrated by what he described as "whingeing" by opposition members.
However, Councillor Grant said: "That's not it at all. We have a job to do as opposition members to scrutinise how he is doing.
"He presides over what is almost a dictatorship.
"The 50 or so Labour councillors never criticise him in public and he gets all shirty when we try to hold him to account and ask him why he has failed to do what he has promised to do."
Coun Grant said he was concerned that Jubilee Square, in St Nicholas' Place, was still incomplete after 11 months of work and a £4 million budget.
The partially-finished square was used for its first public events over the Bank Holiday weekend but is not scheduled for completion until November.
Coun Grant said: "Is the mayor happy with how it looked for its grand opening, with the construction material still around and large bits of it fenced off?
"I'm sure aesthetically it will be an improvement on the car park that was there before. How could it not with a budget of £4 million?
"The businesses nearby were told it would be finished in May. It wasn't. It's massively overrun."
In response, Sir Peter said the square was a "quality public space" and insisted the aim was always to have it usable by the August Bank Holiday. He added that it was remarkable that the square was ready to use in less than 12 months.
Sir Peter had earlier told Coun Porter the Richard III centre, in a building bought and redeveloped by the city council at a cost of just over £5 million, was "bang on target" to reach its projected 100,000 visitors in the first year of opening. It welcomed its 10,000th visitor on Monday, a month after it opened.
However, Coun Porter said 100,000 was a low first year target, and compared the centre with the Nottingham Contemporary art gallery, which attracted 300,000 visitors in its first twelve months.
Although he admitted he had not visited the Richard III centre himself yet, he said he was aware visitors had "not been queuing round the block to get in".
He also said he feared the centre, run independently of the council by a trust, would need to be subsidised.
Sir Peter replied that he was delighted with the visitor numbers so far.
He added: "The whole purpose is there are not queues around the block.
"We want people going in free of hassle, free of rush and free of crowds."