DUBLIN/LONDON (Reuters) - British insurer Legal & General (>> Legal & General Group Plc) said it will move some of its investment management operations to Ireland to ensure it can continue to serve its customers after Brexit, while rival Aviva (>> Aviva plc) is turning its Irish branches into subsidiaries.

In a win for Dublin's campaign to attract financial services firms after Britain's vote to leave the European Union, Legal & General Investment Management (LGIM) will move the operations subject to regulatory approval, L&G said on Friday.

Aviva, meanwhile, is going through the process of converting its Irish life and general insurance branches to regulated subsidiaries to meet the needs of its Irish insurance customers more effectively after Brexit, an Aviva spokesman told Reuters.

LGIM's decision follows plans by rival fund manager M&G, a subsidiary of Prudential (>> Prudential plc), to set up a management company and distribution arm in Luxembourg, which along with Dublin is one of Europe's main hubs for fund services.

LGIM is one of Europe's largest investors, with just under 900 billion pounds of assets under management at the end of 2016, and one of the biggest investors in the UK stock market.

"This is yet another very important signal to the market that financial services companies can come to Ireland quickly and service their European customers, with minimum disruption to their business," said Martin Shanahan, the head of IDA Ireland, the state agency that attracts foreign investment.

L&G said it foresaw no impact on operations and staff in other LGIM locations.

Although asset manager Legg Mason (>> Legg Mason Inc) said in March that it was setting up a management company in Ireland, Dublin missed out on two high profile moves after insurer AIG (>> American International Group Inc) chose Luxembourg and Lloyd's of London [SOLYD.UL] chose Brussels.

L&G and Aviva's decisions are a further boost to Ireland's credentials after JPMorgan Chase (>> JPMorgan Chase & Co.), which currently employs around 500 people in Dublin, said this month it had agreed to buy a building in the city with room for 1,000 staff.

And fellow insurer and asset manager Standard Life (>> Standard Life Plc) said last week that it was likely to choose Dublin as the base for its EU subsidiary after Britain leaves the bloc.

The head of International Financial Services at IDA Ireland said on Thursday that several firms, including insurers, asset managers and banks, had confirmed they had chosen Ireland and announcements would be made from June onwards.

(Additional reporting by Rachel Armstrong in London; editing by Alexander Smith and Susan Thomas)

By Padraic Halpin and Carolyn Cohn