The company said it wants to treat everyone "with fairness and respect" but said the changes were needed to "ensure the future sustainability" of the business.
The news comes after P&O Ferries said it would be forced to cull a quarter of its employees by making them redundant, as the pandemic continues to have a major impact on businesses.
PA reports a Carnival UK spokesman said: "We have begun a period of consultation with our staff in Southampton across all levels of the business.
More from the Merseyside newspaper here.
Afloat.ie adds the Southampton based Carnival UK operation is not to be confused with P&O Ferries which is separately owned by DP World.
As for the P&O Cruises brand this was devested from P&O in 2000 and for a short timeframe became a subsidiary P&O Princess Cruises. By 2003 however the brand following a merger of the cruise company and Carnival Corporation, became part of the US cruise giant which has its headquarters located in Miami, Florida.