More than 400,000 Australians have been notified they may be eligible for a class action accusing National Australia Bank (NAB) of selling “junk” consumer credit insurance (CCI).

Slater and Gordon says at least one in every 50 adult Australians will receive advice of the “insurance rip-off”, in one of the largest court-ordered notices in the nation's legal history.

The law firm alleges NAB sold insurance for credit cards and personal loans which was of little or no value.

“NAB knows that using pushy tactics and pressuring vulnerable customers into buying worthless insurance was wrong. They did it anyway, and collected millions of dollars in unwarranted premiums in the process,” says Practice Group Leader Andrew Paull.

The class action proceedings were filed in the Federal Court in September on behalf of customers who, Slater and Gordon say, were inappropriately sold credit card insurance by NAB and MLC. In June, the court agreed the claim could be expanded to include personal loan insurance.

Australians who paid premiums for NAB Credit Card Cover since September 26, 2012 and/or paid premiums for NAB Personal Loan Cover since June 14, 2013, and meet certain criteria, are eligible to join the class action.