LONDON, July 17 (Reuters) - A new campaign backed by

British retail consultant and television personality Mary Portas

has launched an online petition calling on the new Labour

government to block fast fashion retailer Shein from listing its

shares in London.

China-founded Shein, known for its $5 tops and $10 dresses,

confidentially filed papers with Britain's markets regulator

early last month, two sources told Reuters, kicking off the

process for a potential London listing later in the year.

The campaign accuses Shein of exploiting workers, damaging

the environment and avoiding tax. Some senior UK lawmakers have

questioned Shein's suitability for going public in the UK and

called for greater scrutiny of its labour practices, supply

chain and use of an import tax exemption.

"Shein refutes these inaccurate allegations, which are based

on outdated sources and false claims," the company said in a

statement.

"We are open to engaging with our critics to provide a

true picture. Shein has responded to similar incorrect claims

with tangible evidence of our commitment and investment to

provide a safe and fair work environment across our supply

chain."

Prior to Britain's July 4 election, Labour indicated its

support for Shein listing in London but opposition to the move

is building.

The "Say No to Shein" campaign, which is also backed by

former Green Party lawmaker Caroline Lucas, wants the government

to block Shein's application to list on the London Stock

Exchange until it has completed a thorough investigation into

its labour practices, environmental impact and tax arrangements.

Last month a UK-based human rights group, Stop Uyghur

Genocide, also launched a legal campaign to block any London

initial public offering by Shein.

"Why would we as a country consider embracing a company like

Shein onto the London Stock Exchange?" Portas said on Wednesday.

"This is a company with allegations of unethical business

practices, modern slavery, and violating labour laws. Surely we

are better than this?"

In a statement in May, Shein said it was actively working to

improve suppliers' practices, and investing tens of millions of

dollars to strengthen governance and compliance in its supply

chain.

The petition had been signed by more than 33,000 people as

of July 17.