LONDON, May 6 (Reuters) - Negotiations for the

development of Tanzania's $42 billion liquefied natural gas

export plant have been delayed by proposed government changes to

a financial agreement reached last year, a government

spokesperson and two company sources said.

The government and investors announced last May they had

completed negotiations on the long-delayed project to unlock

Tanzania's vast offshore gas resources.

Equinor ( EQNR ) and Shell are joint operators

while Exxon Mobil ( XOM ), Pavilion Energy, Medco Energi

and Tanzania's national oil company TPDC are partners.

The government said at the time that the cabinet would

review the agreements the following month, but they have not yet

been approved.

Government spokesperson Mobhare Matinyi said Tanzania was

still interested in working with the group of investors.

"The proposed amendment to the Host Government Agreement

intends to ensure that truly both sides benefit fairly in the

whole deal and nothing else," Matinyi said in a statement to

Reuters, without providing details about the amendment.

"We hope that our experts and officials will conclude the

amendments sooner than later to allow this important

project to go ahead."

A source from one of the investors said the amendment was

proposed by Energy Minister Doto Biteko after he assumed the

post last August. Biteko also serves as deputy prime minister.

The proposal "completely blew the project economics out of

the water", said the source, who asked not to be identified. The

source added that remarks last month to parliament by Biteko

saying the government expected to conclude negotiations in the

coming fiscal year were "certainly optimistic".

A second source from another investor agreed with the first

source's account. Neither source provided details about the

amendment.

An energy ministry spokesperson did not respond to a request

for comment.

A Shell spokesperson told Reuters that after initialling the

deals with the government, the company "had hoped to see these

agreements signed faster, but we remain ready to continue to

work with the government on competitive and investable

agreements, consistent with what we agreed last year".

A spokesperson for Equinor ( EQNR ) had no comment. Pavilion and

Medico referred Reuters to Shell. Exxon and TPDC did not

immediately respond to requests for comment.