The British government needs to "step up" over its obligations to hold an inquiry into the murder of Pat Finucane, Taoiseach Micheál Martin has said.
Mr Martin, speaking to the Sunday Times in a wide-ranging interview, said the Irish side had investigated terrorist killings where collusion with security forces was suspected, and reiterated calls for the United Kingdom to reciprocate.
Mr Finucane, 39, who represented republican and loyalist paramilitaries during the conflict, was shot dead in his family home in north Belfast in February 1989 by the Ulster Defence Association (UDA) in an attack found to have involved collusion with the British state.
Northern Ireland secretary Brandon Lewis previously said he was not taking a public inquiry off the table, but said further examinations of the case by police and a police watchdog should conclude first.
Mr Martin told the paper: "The Irish government fulfilled its obligations [under the Weston Park agreement] , the British government hasn't fulfilled all its obligations in respect of the murder of Pat Finucane.
“I think the British government needs to step up on that front as well, and I will work with [them] in relation to that.”
The Smithwick Tribunal into the deaths of two Royal Ulster Constabulary officers – Chief Supt Harry Breen and Supt Bob Buchanan – found that gardaí leaked information to the IRA.
The pair were murdered in 1989 as they crossed the Border following a meeting at a Garda station in Dundalk.
Separately, Mr Martin suggested there was a shared interest between the British intelligence services and IRA not to see “the truth come out” over association between the state and paramilitary organisations relating to murders during the Troubles.
He told the paper: “I think there’s a vested interest among British security interests and Provisional IRA intelligence interests never to have the truth come out.
"I think the Provos would just as well not want it to come out, so they procrastinate on an awful lot of issues and so [does] British intelligence.
“It’s very clear the Provisional IRA was heavily infiltrated in the end.
“There are various inquiries still under way that we’ve never quite got to the bottom of in terms of the level of that penetration, and what it resulted in, in terms of people being killed and murdered, and the work of senior people within the Provisional IRA who turned out to be informers and who caused the deaths of others.” – PA