LONDON (Reuters) - Almost a third of Britain's local government pension schemes object to UK plans to consolidate more of their assets into pooled funds, saying the plans raise the potential for poor investment returns, adviser Hymans Robertson said on Thursday.

The UK government wants to increase pooling of local government assets to boost domestic pensions investment in British companies, including start-ups, because it sees larger pooled funds as better placed to make such investments.

Under the proposals, schemes would be required to take their main investment strategy advice from the new pooled funds.

The 26 local government schemes with pension assets totalling 145 billion pounds ($176.91 billion), 37% of total LGPS assets of 392 billion pounds, say they should retain the ability to choose their own investment adviser, Hymans Robertson said. The schemes signed a proposal put forward by Hymans Robertson that they keep the right to pick their own adviser.

Nearly all funds use investment consultancy services to help on investment strategy, the adviser said.

"Funds should retain the option of using this tried and tested route – and select their adviser," said Iain Campbell, head of LGPS (Local Government Pensions Schemes) Investment at Hymans Robertson.

"This will minimise risk."

Those pension schemes already used some pooled funds but these were "immature in asset or fiduciary terms", Campbell said, adding that the government's timetable to enlarge the funds was "hazardously ambitious".

The government has an initial deadline of March 2025 for the transition of listed assets.

Britain's housing ministry, which issued a consultation on LGPS pooling in November, did not immediately respond to request for comment.

($1 = 0.8196 pounds)

(Reporting by Carolyn Cohn; Editing by Tomasz Janowski)