ST Helena Hospice is set to open two more shops, bringing the total to 12.
It will open branches in Culver Street East, Colchester, and High Street, Dedham – the village’s first charity shop.
It means the Colchester hospice will have doubled its number of stores in just two years.
The Essex Federation of Small Businesses has warned the explosion of charity shops can disadvantage other retailers.
Iain Wicks, development manager, said: “St Helena Hospice is a wonderful charity.
“Supporting a local charity is something very worthy.
“But in terms of competing in the High Street, we have always taken the view charity shops should be selling donated products only.
“There are a number of charity shops moving into the area of selling new products when they have the advantage of 80 per cent business rate discounts.
“They only have one or two paid staff. It puts other retailers at an unfair disadvantage.”
Mr Wicks said a high number of charity shops was never a good sign for a town centre.
He said: “It is one of the signs a high street isn’t being as successful as it could be.”
The hospice’s new store in Dedham will sell high-end items, including designer clothes where the person donating the item will get a cut.
It will replace the Vogue and Vintage shop.
An opening date has not yet been confirmed. The new shop in Culver Street East, Colchester, was previously home to Italian fashion store Brand Village, which opened last autumn.
Opening at the end of the month, it will sell second hand items, as well as having a wedding and occasions section, and a children’s area. The new shops will both employ two members of staff as well as volunteers.
Indira Allen, the hospice’s head of retail operations, said the shops were not in direct competition with businesses.
She said: “We pay charitable concessions rates, but because of this we are limited to what we can sell.”
“A recent report by think tank Demos found there is no evidence charity shops have an adverse economic impact on the High Street.
“The Culver Street East shop was empty and by opening a shop we hope to contribute to the footfall of the vicinity, which will support other businesses.”