Norwegian Pearl exterior

(1:30 p.m. EDT) -- Passengers sailing on Norwegian Cruise Line will soon notice an increase in the automatic gratuities charged to their accounts.

Effective April 1, the line has raised the rates for standard cabins and mini-suites from $13.99 to $14.50 per passenger, per day. Those staying in The Haven and other suites will be charged $17.50 per person, per day -- up from $16.99.

Daily per-person, per-day fees on the line's all-inclusive ships -- Norwegian Sky and Norwegian Sun -- also will increase by one dollar. Standard cabin and mini-suite passengers will see the fees climb from $18.99 to $19.99; suite fees will go up from $21.99 to $22.99. Norwegian revealed the new service charges today in an email issued to its travel partners.

Cruises booked before March 31 will offer the option to prepay gratuities at the current rate, as long as it's done before the sail date. Those with existing reservations, who already prepaid gratuities, will not be affected.

The changes come roughly one year after Norwegian increased its gratuities for the first time in years and only months after it raised the gratuity on its drinks and specialty dining packages from 18 to 20 percent.

Two other mainstream cruise lines -- Royal Caribbean and Celebrity Cruises -- also have raised daily gratuities in recent months.

--By Gina Kramer, Editor