Royal Caribbean Cruises is nothing more than a profiteering vessel to steal cash from nurses in a pandemic ... according to a nurse suing over a cruise canceled by COVID-19.

Jessica Mitchell just filed a class-action lawsuit Wednesday against Royal Caribbean Cruises and NURSECON at Sea, accusing the cruise line and floating convention of conning hard-working nurses out of their deposits for an event scrapped by the coronavirus.

According to new legal docs, obtained by TMZ, Mitchell claims the NURSECON founder is plotting to steal the $2,578 cruise fee from each of the 1,500 nurses who were scheduled to attend before the outbreak scuttled everything.

In the docs, Mitchell says the money grab is particularly bad now, because nurses deserve support now more than ever as they battle COVID-19 on the front lines.

The nurses claim the cruise and convention have refused to grant any refunds despite the cancellation, and instead are pocketing the fees which were paid upfront and offering credit for a future convention which some think may not even happen for years.

In the suit, Mitchell claims the cruise and convention are using the pandemic to line their pockets, and she says there's no reason not to give nurses their money back.

As we first reported ... the voyage was axed due to the pandemic, and nurses were up in arms over the cruise allegedly refusing to grant refunds. However, at the time, Royal Caribbean told us, "Royal Caribbean has been extremely flexible with Nursecon and has provided them with the option to offer their guests a refund on their cruise fare plus taxes and fees, or a 125% future cruise credit."

Adding, "Royal Caribbean deeply appreciates the efforts of our nurses, doctors and health-care professionals working on the frontlines during this public health crisis, and we applaud their sacrifices to help protect our communities."

Mitchell wants nurses to get their money back with interest, plus damages.