The Bishop of London has accused the "wedding industry" of "ramping up expectations of what a big day should involve".
The Right Reverend Sarah Mullally said marriage itself mattered more than the "commercial trappings" of a wedding.
Campaign group What About Weddings called the Bishop's comments "cruel".
Spokeswoman Tamryn Settle said her words "will hurt a huge number of people...who feel their choices have just been trashed".
Speaking in a Lords debate, Bishop Mullally said one of the themes of next month's National Marriage Week was that weddings did not have to be an "expensive extravaganza".
"The fees for a church wedding or a simple registry office ceremony are very modest indeed but the wedding industry is busily ramping up expectations of what a big day should involve," she told peers.
She called on the government to work "to encourage couples to understand that marriage itself matters far more than the commercial trappings of a wedding day".
Baroness Scott of Bybrook, speaking for the government, said: "I am not sure the government can get involved in weddings."
But she added: "I do think that's what been happening through Covid-19 and smaller weddings has, perhaps, made people think that they do not need the huge weddings they have had in the past."
Coronavirus restrictions meant an estimated 220,000 weddings were postponed in 2020.
What About Weddings is campaigning for more government support for businesses facing potential ruin.
'Mental health crisis'
It says the wedding industry employs 400,000 people in the UK, 80% of whom are women, in jobs such as photography, cake-making, catering and dress design.
Ms Settle told BBC News: "It's so disappointing to see that, yet again, 'good' and 'meaningful' weddings are only associated with being 'small' as if this is the only way to really prove you mean your vows.
"What about couples with big families and lots of friends? Or those with cultural or religious expectations that mean large numbers of guests are vital to them and their community?
"Or how about those couples who just want to share their joy and their vows with as many people are possible?"
Ms Settle said she would "welcome the opportunity to discuss the sector with the Bishop in more detail".
"Right now, there is a real mental health crisis in the sector coupled with immediate financial peril for many, and these comments will hurt a huge number of people, both couples and businesses alike, who feel their choices have just been trashed."
Hamish Shephard, co-founder of the Association of British Wedding Business, said more than a million people were planning to get married in the UK over the next 15 months.
"Couples should feel free to celebrate their marriage however they want," he added.
"Whether that is an intimate occasion or complete extravaganza, couples are now older and more financially independent than ever before to celebrate their day their way."