Abbey National Insurance is looking for up to three insurers for its motor panel, Insurance Times can reveal.
The bank, which boasts more than 1.5 million policyholders, is due to go live in May, selling cover via the internet and telesales.
It will use a panel of six to eight insurers.
It has lined up eight possible names, but the list is not yet finalised.
Abbey National currently sells motor insurance underwritten by Norwich Union (NU) via telesales and its 750 branches.
Head of marketing John Grimbaldeston said: "We are still looking for other names.
"We'd probably like two or three of them that perhaps can offer specialist areas."
Niche operators with expertise in covering women drivers, high performance or other non-standard cover could be at an advantage.
Abbey National has moved away from a reliance on NU for its household insurance.
It uses NU for unlimited cover but, since September 2001, has used a panel of insurers to provide cheaper, specified sum policies via the internet.
The household panel comprises AXA, Groupama, Link, MMA, Equity Red Star, Folgate and Fortis.
From May, the cover will also be sold via Abbey National's direct telesales operation which has 250 staff in Liverpool.
From September, the panel's products will be available in the bank's branches.
Grimbaldeston said Abbey National was not rejecting NU's services.
He said: "They are not on our panels and that's their decision. The bulk of our business remains with NU and the relationship is as strong as ever."
Many of Abbey National's customers have bought household insurance and it has sold about 150,000 motor and 170,000 mortgage payment protection policies.
Mortgage protection is its fastest growing area of business and is underwritten by NU.
Abbey National's shake-up is part of a plan to drive forward its insurance business, Operation Trident.
Together with NU and administration and systems firm Capital Insurance Services, Abbey National aims to improve its product range and distribute its products via internet and telesales as well as its branches.
Operation Trident started two years ago.
Claims handling and customer administration was outsourced to
NU and Capita, leaving Abbey National with the product design, sales and distribution.