Nas reportedly owes over $6 million in unpaid taxes.

The rapper is said to have three outstanding liens against him, one from October 2009 for $2,584,236, another from February 2010 for $3,365,671 while the latest one for $514,298 was filed earlier this month.

According to the Detroit News newspaper, Nas also owes $3,860 in fees on his New York apartment.

Nas has been experiencing financial problems for a while and last year he had to sign a payment plan to cover ex-wife Kelis' mortgage.

The 'I Can' hitmaker - who has an 18-month-old son, Knight, with Kelis - had fallen behind on payments so had to shell out double what he was originally ordered to pay to make up for the money owed.

Nas - real name Nasir Jones - was said to be in $300,000 debt to the 'Milkshake' singer and was believed that $52,989.22 of the outstanding monies related to the mortgage.

So he was ordered to pay $14,229.61 a month until he brought the arrears up-to-date.

As well as having to pay her mortgage, Nas was also ordered to pay Kelis $50,000 a month in spousal and child support but because of his money problems a judge recently slashed it to $25,000 a month.

The couple legally split last May, although they called time on their marriage in April 2009 while Kelis was pregnant with Knight.

The 'Acapella' singer cited irreconcilable differences for the reason behind their divorce, although no exact reason for the split has ever been given.