Everton and Liverpool are the only Premier League clubs permitted to allow fans into their stadiums after an announcement from the Government.
Clubs outside Tier 3 in England were allowed 2,000 supporters inside their grounds after the country exited a national lockdown at the start of December.
Liverpool supporters returned to Anfield for the first time against Wolves earlier this month, whilst 2,000 watched Everton beat Chelsea 1-0 at Goodison Park.
However, the rapid rise in COVID-19 cases across the South, in particular London, has seen more areas moved into Tier 3 and even Tier 4, leaving Merseyside as the only Premier League area that can house supporters.
Arsenal, Chelsea, Tottenham, West Ham and Crystal Palace lost that privilege last week and now Southampton and Brighton & Hove Albion have joined them on the list in Tier 4.
This follows the discovery of a new, more transmissible strain of coronavirus, and a significant rise in the number of cases reported across all areas of Sussex and Hampshire in the most recent figures.
Mr Hancock said: "We know that Tier 3 is not enough to control the new variant.
"This is not a hypothesis, this is a fact. We've seen it on the ground.
"We've seen case rates rise in some of the places close to where the current Tier 4 restrictions are.
"It is therefore necessary to put more of the east and south-east of England into Tier 4."
Supporters remain allowed inside Anfield and Goodison Park with Merseyside remaining in Tier 2.
