An acting Prime Minister is a Cabinet

Cabinet (government)

A Cabinet is a body of high ranking government officials, typically representing the executive branch. It can also sometimes be referred to as the Council of Ministers, an Executive Council, or an Executive Committee.- Overview :...

 member (often in a Commonwealth

Commonwealth

Commonwealth is a traditional English term for a political community founded for the common good. Historically, it has sometimes been synonymous with "republic."More recently it has been used for fraternal associations of some sovereign nations...

 nation) who is serving the role of prime minister

Prime minister

A prime minister is the most senior minister of cabinet in the executive branch of government in a parliamentary system. In many systems, the prime minister selects and may dismiss other members of the cabinet, and allocates posts to members within the government. In most systems, the prime...

, whilst the individual who normally holds the position in unable or unwilling to do so. The role of Acting Prime Minister is often performed by the Deputy Prime Minister

Deputy Prime Minister

A deputy prime minister or vice prime minister is, in some counties, a government minister who can take the position of acting prime minister when the prime minister is temporarily absent. The position is often likened to that of a vice president, but is significantly different, though both...

. The office is also commonly used when the prime minister is absent from the territory of that nation. An Acting Prime Minister should not be confused with a caretaker prime minister

Caretaker government

Caretaker government is a type of government that rules temporarily. A caretaker government is often set up following a war until stable democratic rule can be restored, or installed, in which case it is often referred to as a provisional government...

, which refers to an outgoing prime minister following an electoral defeat, and who by convention

Convention (norm)

A convention is a set of agreed, stipulated or generally accepted standards, norms, social norms or criteria, often taking the form of a custom....

 does not implement new policies or an Interim Prime Minister who is appointed to perform a similar role to a Caretaker Prime Minister, but who is typically not a prime minister at the time of being appointed.

Statutory authority

Within a Commonwealth nation, the office of Acting Prime Minister, like that of Prime Minister is found only in convention, and is not legislated. The Department of Prime Minister and Cabinet, or an equivalent ministry, drafts, reviews and publishes any formal conventions (though these are expressly non-binding in a court of law).

• Politics of Australia
  Politics of Australia
  The Politics of Australia take place within the framework of a parliamentary democracy, with electoral procedures appropriate to a two-party system. Australia is governed as a federation and as a constitutional monarchy, with an adversarial legislature based upon the Westminster system...
  
  
• Westminster Conventions
  Convention (norm)
  A convention is a set of agreed, stipulated or generally accepted standards, norms, social norms or criteria, often taking the form of a custom....
  
  

Acting Prime Ministers

• Acting Prime Minister of Canada