BENGALURU (Reuters) -Accounting giant Deloitte is acquiring some of rival PricewaterhouseCoopers' (PwC) Maldives and Sri Lanka network firms, according to a Deloitte memo seen by Reuters, strengthening the company's presence in the South Asia region.

After the deal, one of the largest such combination deals in the region, Deloitte will have 28 partners and 800 people, a person with direct knowledge of the matter said.

PwC's Sri Lanka and Maldives firms will join Deloitte with effect from Oct. 28, the memo said.

A Deloitte spokesperson confirmed the deal but did not disclose financial or other terms.

Deloitte and PwC are part of the so-called global Big 4 accounting giants, along with EY and KPMG whose services include audits, tax and risk advisory.

PwC Sri Lanka and Maldives also confirmed the Deloitte deal in a separate memo sent to some clients seen by Reuters. We are "committed to effecting a seamless transition as we prepare to join Deloitte," the memo said.

PwC did not immediately respond to a Reuters request for comment.

"This is a transformative chapter in our history and marks a strategic leap forward," Deloitte South Asia CEO Romal Shetty said in the memo.

Deloitte already has a presence in Sri Lanka, largely providing audit services in the region, the source with direct knowledge said. The new deal with PwC will help it offer advisory services and "especially technology consulting," the source said.

Deloitte will become Sri Lanka's second largest professional services firm behind KPMG, the source said.

Deloitte reported global revenues of $64.9 billion for the financial year ending May 31, up 14.9% in local currency.

(Reporting by Nandan Mandayam in Bengaluru and Aditya Kalra in New Delhi; Editing by Pooja Desai and Mark Potter)