(Reuters) -UnitedHealth Group ( UNH ) said on Friday it expects more than $14 billion in medical claims to start flowing soon through its unit Change Healthcare as several services for handling them gradually come online over the next few weeks following a hack last month.

The health insurer said its software for preparing medical claims Assurance went online on Monday, while its largest clearinghouse Relay Exchange will resume on the weekend of March 23.

The cyberattack has disrupted payments to U.S. doctors and healthcare facilities nationwide for a month, especially community health centers that serve more than 30 million poor and uninsured patients.

UnitedHealth ( UNH ) had suspended paperwork required to get approval for insurance coverage for most outpatient services, as well as review of inpatient admissions for government-backed Medicare Advantage plans to help those impacted.

The insurer said it will work with payers to ensure there are a maximum number of available locations for claims and is actively coordinating with other clearinghouses to make sure there are no capacity issues.

A clearinghouse acts as a middleman between a healthcare provider and a health plan that checks claims to ensure they do not contain errors before forwarding them for payment.

UnitedHealth ( UNH ) also expects to engage all those who submitted claims during the week of March 25.

The company's other products that handle eligibility of claims such as Clearance and Coverage Insight as well as pharmacy claims submission software MedRx and Reimbursement Manager are expected to go online next week.

Several more products are likely to go online over the weeks of April 1 and April 8, the company said.

Some products, however, were not listed in Friday's update as it does not yet have clarity of when they will be restored, the company said, adding it will provide updated information as those timelines become clear.

Change Healthcare, which processes about 50% of medical claims in the U.S. for around 900,000 physicians, 33,000 pharmacies, 5,500 hospitals and 600 laboratories, was breached on Feb. 21 by a hacking group called ALPHV, also known as "BlackCat".