Shadow health secretary Jonathan Ashworth said the government had failed to give people in Leicester enough information about the local lockdown.
The MP for Leicester South made the comments as local residents and businesses also expressed frustration at the “lack of guidance”.
Mr Ashworth told ITV’s Good Morning Britain residents were anxious and “very, very scared”.
The government said it had taken steps to provide all the information needed.
Health secretary Matt Hancock announced at 21:15 BST on Monday that people in the city would face tighter restrictions over the next fortnight in response to a spike in coronavirus cases.
Measures include the closure of shops selling non-essential items, schools being closed to most pupils and a block on non-essential travel.
But residents have expressed to the BBC confusion over who they can and cannot see as well as questioning what constitutes essential travel.
A map showing which areas fell within the lockdown zone was also not made public for more than 12 hours after Mr Hancock’s announcement.
A postcode tool allowing people to check whether they lived inside the affected area was launched by the county council on Tuesday evening.
James West, who owns a printing shop just inside the lockdown boundary in Thurmaston, said he opened as usual at 09:00 on Tuesday, only for the map to be released about an hour later, forcing him to close.
The 25-year-old said he was “greatly frustrated with the lack of guidance”.
Indy Burmi, who owns two hair salons – one inside the lockdown area and one outside – said he was worried about the impact on his business.
“The grant we had from the council [at the start of lockdown], which was a great help, has totally vanished on bills, without paying rent,” he said.
Mr Ashworth said the introduction of the lockdown was “slow” and had left people “still asking for information”.
“People are really worried in Leicester, people are going to be anxious,” he said. “People who are shielding are very, very scared.
“The police commissioner is complaining they’ve been drip-fed information about what they can and can’t enforce.
“People want clarity. People want to do the right thing. They just want some clear guidance.”
The prime minister’s official spokesman said: “Both nationally and locally steps have been taken to ensure that people have all the information they need.”
The lockdown is due to be reviewed on 18 July.
‘Engaging, explaining, encouraging’
Leicestershire’s police and crime commissioner Lord Willy Bach has said law enforcement had received “minimal guidance” on the restrictions.
Officers dealt with 83 complaints about breaches of Covid-19 restrictions on Tuesday, Leicestershire Police said.
Chief Constable Simon Cole said the force would assist with the lockdown “using lots of common sense” and “by doing what we’ve been doing all the way through – engaging, explaining, encouraging and – where we need to – enforcing”.
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