Acting Chief Minister Katy Gallagher said yesterday the Government did not reject the Hume site and it had no involvement in the decision selecting the site next to Mugga Lane in Tuggeranong.

Her comments followed a Canberra Times report on documents obtained under Freedom of Information provisions. The documents revealed a letter from Chief Minister Jon Stanhope to then-ActewAGL chief executive officer John Mackay stating, ''I have instructed Government officials to continue to liaise with your representatives to finalise a preferred site ...''

The Chief Minister's Department deputy chief executive, David Dawes, told the estimates committee last month the department had not been involved in site selection.

Mr Dawes told The Canberra Times on Friday he had written to the estimates committee apologising for saying the department had not been involved, when it had.

Yesterday, Ms Gallagher said MrStanhope's letter just showed ''the Government remained interested and excited by this proposal''.

''The Government wanted to make sure that the appropriate support was given to the proponents in choosing ultimately the preferred site,'' she said.

''It's just an ongoing facilitation role.''

Documents, obtained by the ACT Opposition, also revealed a memo from Mr Dawes, saying ActewAGL had chosen the Mugga Lane site. ''This is the preferred option for the territory too, as it retains the existing and proposed industrial land for release to the market,'' the memo states.

A later document again showed the Chief Minister's Department thought the Tuggeranong site was the ''best outcome'' because it would keep the industrial land available for the open market.

But Ms Gallagher said she understood ActewAGL was not told the Tuggeranong site was the Government's preferred site for the project before any decision was made.

''The Opposition will not be able to prove, in any way, in any document that there was any improper involvement, or ultimately that the Government took decisions around this project specifically about where it was, because that's just not the case,'' she said.

ActewAGL considered four sites to build the gas-fired power station and data centre two at Tuggeranong and two at Hume.

Mr Dawes said all four sites, including the current site proposed for the project, were within about 500m of one another.