Tony Blair is likely to face tough questions over plans to detain terror suspects without trial, during his monthly press conference.
Mr Blair is expected to announce a rise in the minimum wage
Both the Lib Dems and Tories oppose the plan - but Mr Blair said it was needed to combat potential suicide attacks.
London's police chief Sir Ian Blair has warned terrorists could strike in the run up to an election, expected in May.
Mr Blair is also likely to be pressed on the royal wedding and minimum wage during the televised event.
Home Secretary Charles Clarke is reportedly ready to offer concessions to critics of the Prevention of Terrorism Bill.
At issue are "control orders", which as well as placing suspects under house arrest could be used to impose curfews, tagging or bans on telephone and internet use.
They would replace current powers to detain foreign terror suspects without trial, which the law lords have ruled against.
But critics are concerned that it would be the home secretary and not judges who decided to impose control orders.
Mr Blair has already faced attacks from Tory leader Michael Howard who accused him of "steamrolling" the plans through parliament and of "using national security for political point scoring".
Liberal Democrat leader Charles Kennedy says the measure is a further example of Labour's "authoritarian" response to the terror threat.
The Commons has approved the measures despite considerable opposition, with the government's majority more than halved as 32 Labour rebels joined Tory and Lib Dem opposition.
Mr Blair insists it would be wrong to wait for an attack before acting.
Sir Ian Blair, the Metropolitan Commissioner, warned of the prospect of a terrorist attack in the run-up to the election.
He said terror groups would remember the effect of the Madrid bomb on Spain's general election last year.
Other potential targets were the royal wedding and the UK's presidency of the European Union and G8, he said.
During the press conference Mr Blair is likely to be quizzed abut the fraught preparations for the marriage of the Prince of Wales and Camilla Parker Bowles.
Lord Falconer, the Lord Chancellor, was forced to publish his legal advice to the Royal Family after mounting speculation that the marriage would be illegal.
The Queen and the Duke of Edinburgh have announced they will not be attending their son's civil marriage.
The Tories have said they would back a bill to clear up any doubts, even though the government has insisted no legislation is necessary.
Mr Blair is also likely to use the televised briefing to announce a rise in the minimum wage.
The Low Pay Commission, which advises ministers on the issue, is reported to want the minimum wage to increase to £5.05 in October and £5.30 next year.
Mr Blair is expected to back the recommendation.
Lord Falconer's involvement in drafting a ministerial answer from Attorney General Lord Goldsmith on the legal advice given to justify the Iraq war is also likely to be raised at the conference.