A leaked internal survey shows spies' morale "declined dramatically" over four years.

The Government Communications Security Bureau (GCSB) probed staff in June last year about their view of the agency.

It was the first staff survey since 2007 and revealed "climate has gone down across the board".

The bureau has been under fire since it was revealed it illegally spied on internet mogul Kim Dotcom last year. A review revealed three more potential cases of unlawful behaviour.

The documents, leaked to The Dominion Post, show restructuring, moving premises and issues over pay have left staff "feeling less engaged with GCSB". The move to a new Wellington building was "poorly organised - and created more tension than solved", staff said.

One spy said a management review was "a good idea, but the endless delays have resulted in a lack of belief that anything useful will ever come from it".

Another talked of "numerous reviews costing a lot of money which inevitably end up with more management and less direction".

A new remuneration system is "overly complicated and flawed", while staff were "quitting in droves" over the new pay scheme, two others said.

One comment, highlighted by the survey's authors, said: "We have many long-serving employees. Quite often people are promoted due to length of service rather than competence . . . also, if you have a good relationship with a senior manager and are therefore known to them your chance of being promoted is greater."

The survey questioned staff on a number of "climate factors", such as "clarity" (how an organisation understands and articulates its functions), "drive" and "confidence".

GCSB scored lower than the public sector's benchmarks on almost all factors. Overall, 72 per cent of staff said they were committed to the agency - compared with 81 per cent in 2007.

In the last month, the agency has been criticised for its errors over Dotcom - and for not adequately briefing Prime Minister John Key.

The report suggested "improving communication between all levels of the organisation" and warned poor communication would "likely impact on perceptions of the effectiveness of the bureau, which have declined since 2007".

- © Fairfax NZ News