Kourtney and Khloe Kardashian are ''obsessed'' with their new niece.

The reality TV stars' sister Kim gave birth to her first child, daughter North West, last month and the proud aunts love spending as much time as they can with the baby.

A source told People magazine: ''Kourtney and Khloe are obsessed. Kourtney has been great with advice, from baby gear to reassuring Kim in all her decisions. The family is really supportive.''

Kourtney has also introduced North to her cousins - Mason, three, and 11-month-old Penelope, her children with partner Scott Disick - and all the kids have been getting on great.

North's father Kanye West has been documenting every moment of the tot's life so far and is rarely seen without his camera because he doesn't want to miss a minute of her first few weeks in the world.

The source added: ''Kanye wants to know how to do everything and be able to hold and soothe her. He's been documenting everything. He doesn't want to miss a moment.''