American Express Co. has introduced an online invoicing and payment service aimed at small businesses.

The company's AcceptPay, announced Monday, enables businesses to produce, send and track invoices electronically. Clients can pay with credit and debit cards, checks, electronic debits and other methods.

AcceptPay is offered through Amex's Open unit, which targets small-business clients.

Amex said the service could help users get paid faster and comes at a time when many clients are slower in paying, resulting in cash flow problems at some small businesses.

According to Amex research, 60% of small-business owners have cash flow concerns, and many say that improving collections is an effective method to improve cash flow.

Businesses need not have Amex cards to sign up for the service. There is no setup fee for AcceptPay, and users pay $20 per month.

"At a time when every dollar counts, business owners need tools and resources to help them better manage their firms' finances, and that is why we created this innovative payment collection" service, Mary Ann Fitzmaurice Reilly, a senior vice president with Amex's Open unit, said in a press release.